Sightings of redback and white- tailed spiders have peaked in recent weeks.

But Mr Fearn said it was just a perception there were more spiders in the city at the moment.

"The really warm weather generates a lot of activity in spiders," he said.

"People are just seeing more of them because they're moving around more."

The honorary associate researcher with the Queen Victoria Museum and Art Gallery said both types of spiders were extremely common throughout Launceston.

"There are hundreds of thousands of these spiders across the city," he said.

"It's just that most of the time they're hidden away where people don't see them."

Mr Fearn said white-tailed spiders were very useful to have around the house.

"Their primary prey is other spiders and they don't make webs," he said.

"And I've never heard of anyone dying from a white-tailed spider bite."

Bites from redback spiders were also not as serious as people seemed to believe, Mr Fearn said.

"Male redbacks are a fraction of the size of females and are absolutely harmless," he said.

"While a bite from a female redback is incredibly painful, it is highly unlikely to kill you."

Mr Fearn said unless a person interfered with where a female was living, they would not be bitten.

"They like draughty, hot and dry conditions," he said.

"Don't go rummaging under old sheets of roofing iron, avoid sticking your hand up or behind draining pipes, and you should be alright."