The potentially deadly spider appears to be on the prowl much earlier this season, with sightings increasing over the past month in the Sydney metropolitan area.

In November a two-year-old boy was bitten at Cooranbong, near Lake Macquarie, when a funnel web got into his gumboot.

Gerringong-based arachnid expert Graham Wishart believes the numbers of the creepy critters in the Kiama and Wollongong areas are not extraordinary, but he urged people to take precautions to avoid being bitten.

"They are certainly more prevalent at this time of year, particularly after it has just rained," Mr Wishart said.

"They need the moisture to move around and this is the time of year when the males are wandering around trying to find nests that contain females."

During the past year, Mr Wishart has been busy discovering new species of trapdoor spiders, a cousin to the funnel web spider, and has uncovered 12 new species in the Kiama region alone.

Funnel webs go in search of dark spaces such as shoes, cavities around the house, into the folds of towels and between garden rockeries.

The last time a funnel web killed someone was in early 1980, when a two-year-old boy was bitten.

Funnel web anti-venom became available that year and no-one has died from a bite since.

Up to 12 people are bitten each year in Australia, and most of those bites could have been fatal if help had not been immediately sought.

Symptoms of a funnel web bite include vomiting, convulsing and severe difficulty breathing.

About 40 species of the funnel web spider live in Australia, with the deadliest located on the east coast, between Toowoomba and the Victorian boarder.

The paperbark funnel web is the most poisonous species, with a bite that requires up to 17 ampules of anti-venom to treat one victim.