- The Avondale Spider holds the overall leg-span record in NZ at up to 200 mm, while the Nelson Cave Spider is the largest endemic species at up to 150 mm.
- Tunnelweb spiders (Porrhothele antipodiana and Hexathele hochstetteri) are the heaviest NZ spiders by body mass and are commonly encountered in Kiwi homes during autumn.
- New Zealand has no spider species capable of causing serious medical harm to healthy adults — even the largest species are essentially harmless.
- The Nelson Cave Spider is protected under the Wildlife Act and is found only in caves within the Nelson–Buller–Kahurangi region of the South Island.
- Fishing spiders (Dolomedes spp.) are large, semi-aquatic hunters capable of walking on water and catching small fish, found near streams and wetlands throughout NZ.
New Zealand is home to some genuinely impressive arachnids, and if you’ve ever wondered what the biggest spider in NZ actually is, the answer depends on how you measure it. Leg span, body bulk, and sheer visual impact each point to a different contender. In this guide you’ll meet the top candidates — from the reclusive Nelson Cave Spider lurking in South Island caves to the cinematic Avondale huntsman of suburban Auckland — and get the facts you need to identify, understand, and appreciate them.
Why Defining the ‘Biggest’ Spider in NZ Is More Complicated Than You’d Think
Ask ten people which is the biggest spider in New Zealand and you’ll likely get several different answers — and they’d all have a point. Spider size can be measured by leg span, body length, or body mass, and different species dominate each category. Arachnologists typically use leg span as the primary measurement for comparing spider size, but a spider with a wide leg span can still be remarkably light, while a compact, stocky species may outweigh it considerably.
There’s also the native versus introduced distinction to consider. New Zealand has a rich suite of endemic spider species that evolved here in isolation over millions of years, plus a handful of introduced species that have settled in comfortably — sometimes a little too comfortably. When Kiwis talk about our biggest spiders, both groups deserve a place at the table. The sections below cover the main contenders across each size category, so you can decide which title fits the species you’ve just spotted in your shed — or on your ceiling.
The Nelson Cave Spider: New Zealand’s Largest Endemic Species
When it comes to native giants, the Nelson Cave Spider (Spelungula cavernicola) is the undisputed record-holder by leg span among endemic New Zealand spiders, reaching an impressive 130–150 mm from tip to tip. Despite that extraordinary measurement, its body length sits at roughly 3 cm, giving it a deceptively delicate appearance for something so architecturally large.
This spider is considered a relict species — a living relic of an ancient lineage that has changed little over millions of years. Researchers believe it represents a significant evolutionary link between primitive and more modern spider families. Its entire known range is restricted to caves in the Nelson, Buller, and Kahurangi National Park regions of the South Island, making it one of the most geographically limited large spiders on the planet.
Rather than spinning webs, the Nelson Cave Spider is an active ambush predator, positioning itself on cave ceilings and dropping onto cave wētā below with remarkable precision. Its restricted, specialised habitat made it vulnerable enough that DOC closed the famous Crazy Paving Cave in 2022 to protect breeding populations from disturbance caused by foot traffic. Fittingly, it holds the distinction of being the first spider species in New Zealand to receive protection under the Wildlife Act.
Nelson Cave Spider at a Glance
| Feature | Detail |
|---|---|
| Scientific name | Spelungula cavernicola |
| Maximum leg span | 130–150 mm |
| Body length | ~30 mm |
| Native status | Endemic — found only in NZ |
| Conservation status | Protected under the Wildlife Act |
| Bite risk | Low; painful but not medically significant |
The Avondale Spider: New Zealand’s Largest Introduced Resident
If you’re searching for the biggest spider in NZ by total leg span — native or otherwise — the Avondale Spider (Delena cancerides), also known as the Social Huntsman, claims that crown with a maximum leg span of up to 200 mm. Originally from Australia, this species is believed to have arrived in New Zealand during the early 1920s, most likely hitching a ride in hardwood timber shipments. It established itself in the Auckland suburb of Avondale, and the name has stuck ever since.
What makes the Avondale Spider genuinely fascinating isn’t just its size — it’s its unusual social behaviour. Most spiders are fiercely solitary, but Delena cancerides lives in communal colonies of up to 300 individuals, sharing food and cohabiting under tree bark or inside residential roof cavities. This cooperative lifestyle is rare among arachnids globally, and it’s partly what makes them so manageable around humans: they’re not territorial or aggressive in the way a solitary huntsman might be when cornered.
Their flat, crab-like body shape allows them to squeeze into remarkably thin spaces — behind picture frames, under corrugated iron, in garden sheds. Sightings are most common in Auckland but have also been recorded in Christchurch. And yes, the cinema claim is genuine: 374 Avondale Spiders were used on set during the filming of the 1990 Hollywood movie Arachnophobia, selected precisely because of their impressive size and calm temperament around film crews.
Head-to-Head: Avondale Spider vs. Nelson Cave Spider
Both species regularly compete for the ‘biggest spider in NZ’ title, so it helps to compare them side by side. The key difference comes down to origin, behaviour, and where you’re likely to encounter them.
| Metric | Avondale Spider | Nelson Cave Spider |
|---|---|---|
| Max leg span | Up to 200 mm | Up to 150 mm |
| Body shape | Flat, crab-like | Robust, mottled brown |
| Social behaviour | Highly social — colonies of up to 300 | Solitary |
| Native status | Introduced from Australia | Endemic to New Zealand |
| Primary location | Urban Auckland and Christchurch | Caves in Nelson–Buller–Kahurangi |
| Danger to humans | Essentially harmless | Bite painful, not toxic |
Tunnelweb Spiders: The Heavyweights by Body Mass
If sheer bulk and body mass are your measure, then the tunnelweb spiders are serious contenders for the biggest spider in NZ title. The Black Tunnelweb (Porrhothele antipodiana) and the Banded Tunnelweb (Hexathele hochstetteri) are stocky, densely built arachnids that genuinely resemble miniature tarantulas — hairy, robust, and with a presence that commands attention.
These spiders are a regular autumn and spring sight in Kiwi homes, as wandering males search for mates and stumble through gaps in door frames and window seals. They build distinctive thick, white silk tunnels in garden beds, compost heaps, and under logs, which are easy to spot once you know what you’re looking for. When disturbed, they adopt a dramatic defensive posture — rearing up and displaying their fangs — though they strongly prefer to retreat into their tunnels rather than make contact.
Female tunnelwebs are long-lived by spider standards, with some individuals in captivity surviving beyond ten years. Their bites are capable of causing localised pain and swelling but are not considered medically dangerous to healthy adults.
Tunnelweb Species Comparison
| Species | Body Length | Key Identifying Feature |
|---|---|---|
| Black Tunnelweb (Porrhothele antipodiana) | Up to 30 mm | Solid dark brown to black, shiny cephalothorax |
| Banded Tunnelweb (Hexathele hochstetteri) | Up to 25 mm | Distinctive colour bands across the abdomen |
Giant Fishing Spiders: New Zealand’s Aquatic Hunters
New Zealand’s fishing spiders (genus Dolomedes) are a remarkable group that deserve far more recognition than they typically get. These large, semi-aquatic spiders are capable of walking on water, detecting vibrations through the surface film to locate prey — including small fish and aquatic invertebrates — which they then seize with startling speed.
The largest of New Zealand’s fishing spiders is Dolomedes schauinslandi, endemic to the Chatham Islands, which can achieve a leg span approaching 100 mm. On the mainland, Dolomedes aquaticus and Dolomedes dondalei are the species most likely to be encountered near streams, rivers, and wetlands. Their bodies are patterned in earthy browns and creams, providing excellent camouflage against rocky streambeds and leaf litter.
Fishing spiders don’t build webs to catch prey. Instead, they rest at the water’s edge with their front legs touching the surface, essentially using the water as a sensory extension of their body. They’re entirely harmless to humans and are considered beneficial predators in riparian ecosystems, helping to regulate aquatic insect populations.
Garden Sheet-Web Spiders and Other Sizeable NZ Residents
Not every large spider in New Zealand is a cave dweller or a huntsman. The sheet-web spiders (family Linyphiidae) are ubiquitous in New Zealand gardens, farmland, and forest edges, and while none rival the leg spans of the species above, some of the larger members of this group are frequently mistaken for more dangerous species by Kiwis who aren’t familiar with them.
Sheet-web spiders construct their characteristic flat, horizontal silk sheets close to the ground, often visible on dewy mornings when the web catches the light. They hang upside-down beneath the sheet, waiting for insects to stumble across the surface. They are entirely harmless, ecologically valuable, and an encouraging sign of a healthy garden environment.
Other notable large spiders you might encounter in New Zealand include the vagrant spider (Uliodon spp.), a fast-moving ground hunter found under bark and in leaf litter, and the impressive nursery-web spider (Dolomedes minor), which carries its egg sac by mouth and builds a silk nursery tent to protect newly hatched spiderlings.
Spider Safety and What to Do If You Find a Large Spider Indoors
Finding a large spider inside your home is a startling experience, but it’s worth keeping perspective: New Zealand has no medically dangerous spider species capable of causing serious harm to a healthy adult. The two species most often cited as capable of causing medical issues — the katipō (Latrodectus katipo) and the introduced redback (Latrodectus hasselti) — are small, not large, and bites requiring treatment are extremely rare.
If you find a large spider indoors, the best approach is straightforward:
- Don’t panic — remind yourself it is almost certainly harmless and more startled than you are.
- Use a container and a piece of card to gently cover and slide under the spider, then take it outside.
- Release it into the garden where it will get on with the useful business of eating insects.
- Seal gaps around doors, windows, and pipes if repeated indoor visits are a concern.
- Contact a local entomologist or iNaturalist NZ if you want to have an unusual specimen identified accurately.
Appreciating spiders — even the big ones — is a bit like appreciating a well-played hand of solitaire: it rewards patience and a willingness to look closely at what’s in front of you. And just as understanding the common mistakes poker beginners make helps you play smarter, knowing what you’re actually looking at makes a big spider far less intimidating.
New Zealand’s spider fauna is a genuine taonga — a treasure of evolutionary history and ecological function. Whether you encounter a tunnelweb in your compost bin or spot the silhouette of a fishing spider at dusk on a riverbank, you’re looking at millions of years of adaptation to this remarkable country’s environment. That deserves a moment of appreciation, even if it also deserves a respectful distance.
Frequently Asked Questions
What is the biggest spider in New Zealand by leg span?
The largest spider in New Zealand by leg span is the introduced Avondale Spider (Delena cancerides), which can reach up to 200 mm across the legs. Among native endemic species, the Nelson Cave Spider (Spelungula cavernicola) holds the record, with a leg span of up to 150 mm. Both are essentially harmless to humans despite their impressive dimensions.
Is the Nelson Cave Spider dangerous?
The Nelson Cave Spider is not considered medically dangerous. Its bite has been described as painful — comparable to a wasp sting — but it produces no venom known to cause serious harm to humans. The greater concern with this species is human impact on its habitat: it is legally protected under New Zealand’s Wildlife Act, and its cave environments are carefully managed by DOC to prevent disturbance.
Where can I find the Avondale Spider in New Zealand?
The Avondale Spider is most commonly found in Auckland, particularly in older suburbs with established gardens and weatherboard houses. It tends to shelter under bark, behind picture frames, in roof spaces, and under corrugated iron. It has also been recorded in Christchurch. Because it lives in colonies of up to 300 individuals, finding one often means others are nearby — though they pose no threat.
Are tunnelweb spiders the same as funnel-web spiders?
New Zealand’s tunnelweb spiders are often confused with the deadly Australian funnel-web spider, but they are entirely different species and far less dangerous. New Zealand tunnelwebs — including Porrhothele antipodiana and Hexathele hochstetteri — can deliver a painful bite but have no venom capable of causing serious medical harm. They are, however, visually similar: robust, hairy, and impressively built.
What should I do if I find a large spider in my home?
Stay calm — New Zealand’s large spiders are not medically dangerous. Use a glass or container and a piece of stiff card to carefully capture the spider, then release it outside into the garden. Avoid handling it directly, not because it’s dangerous but to avoid stressing the animal. If you’re unsure of the species, photograph it and upload the image to iNaturalist NZ for a community identification.
