Scientists have stumbled upon a possible new species of funnel-web spider near Jervis Bay on the New South Wales south coast.

Scientists from the Australian National University found the large female spider burrowed in a rotting log in the Booderee National Park during a study of the area's biodiversity.

Biologist Dr Thomas Wallenius said the spider was around five centimetres long and believed to be up to 30 years old.

ANU biologist Dr Thomas Wallenius discovered the female spider in a rotting log. ( Supplied )

"The spiders moult as they approach maturity and judging by her size we are able to estimate that she was probably around about 25 to 30 years," he said.

"We are not entirely sure how long they do live for... but the upper limits of age may be further than 30 years."

Dr Wallenius believed the spider was a species of the tree-dwelling genus Hadronyche, not the ground-dwelling genus Atrax commonly found in Sydney.

"It's remarkable that we have found this ... in the Booderee National Park," he said.

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

"We are also interested in finding out whether Atrax or the Sydney funnel-web actually also occurs in that area."

Genetic testing to determine species status

To date there have been 13 recorded deaths from funnel-web bites, but none since the antivenom was developed in 1981.

The Jervis Bay area is well known for its funnel-web activity, with the antivenom being developed by scientist Struan Sutherland after the death of a seven-year-old girl who was bitten in the area.

Generic testing will now be conducted to determine if the female was part of a previously undiscovered species.

The female funnel-web spider found by scientists could be up to 30 years old. ( Supplied: Stuart Hay ANU )

"We are investigating what that spider is at this point in time. We are uncertain how that fits into current classifications," Dr Wallenius said.

"We would like to do genetic and morphological analysis."

The discovery was part of a larger biodiversity study of the area.

"We are basically in the area having a look and just trying to get a little bit more of an idea of the biodiversity of the area."

"Two funnel-web species are known from the area but we are doing a little bit more of a thorough investigation of the types of funnel-webs that have been found, and doing our own collections as well."

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.

"They build a silk-lined burrow inside the hollow log which can be up to two metres long," he said.

"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."