Scientists studying funnel-web spiders at Booderee National Park near Jervis Bay on the New South Wales south coast have found a large example of an unexpected funnel-web species.

The scientists believe the 50-millimetre spider is a species of the tree-dwelling genus Hadronyche, not the ground-dwelling genus Atrax, which includes the Sydney funnel-web, the only species reported in the Park's records.

"It's remarkable that we have found this other species in Booderee National Park," said Dr Thomas Wallenius, from The Australian National University (ANU).

"It shows we still have a lot to learn about what's out there in the bush.

"It may even turn out to be a new species of funnel-web," said Dr Wallenius, a biologist in ANU Research School of Biology.

There have been 13 recorded deaths from funnel-web bites, and none since an antivenom was developed in 1981. The development of an antivenom was prompted when scientist Struan Sutherland heard of the death of a seven-year-old girl who was bitten by funnel-web near Jervis Bay.

The discovery of the spider is part of a larger biodiversity study of the area, Dr Wallenius said.

"The Jervis Bay region has a wide variety of both plant and animal species, as northerly and southerly ocean currents meet, which makes it a rich area to study," he said.

Dr Wallenius was searching for funnel-webs in Booderee National Park when he found the female funnel-web in her lair, burrowed into a rotting log.

"They build a silk-lined burrow inside the hollow log which can be up to two metres long. She had probably been living in there for 25 to 30 years," he said.

Dr Wallenius said other spiders are often mistaken for funnel-webs, so members of the public should not panic if they think they have found one.

"The males are more likely to be encountered in the summer months, and may be more aggressive, but contrary to common belief funnel-webs can't jump."