Perth's highest winter rainfall in five years may be good for gardens, but the health department is warning that it may also mean an onslaught of mosquitoes as the weather warms up.

More rainfall and predictions of above-average high tides in the coming months means there would be more stagnant water around for mosquitoes to breed in as spring progresses.

"All of that combined is telling us that we are probably in for a busier year, for mosquitoes, than in other years," Dr Michael Lindsay from the WA Department of Health told 720 ABC Perth.

In addition to the irritation and itching mosquito bites cause, Dr Lindsay said they can also spread serious diseases like Ross River virus and the less well-known Barmah Forrest virus.

"The symptoms of both are painful swollen joints, sore muscles, and Barmah Forrest in particular can have quite a significant rash," he said.

"People also have other symptoms typically associated with viral infections such as fever, fatigue and headache.

"Those symptoms can persist for weeks and in some cases months.

"It's not a thing to take lightly; it does have a very significant impact on quality of life."

There are no registered vaccines for either virus and treatment involves managing with the symptoms with painkillers and anti-inflammatory medications.

How to avoid bites

Stagnant water in backyards gives mosquitoes a place to breed. ( Tim Hurst )

The best prevention is to try to avoid mosquito bites altogether.

At home that means trying to eradicate potential mosquito breeding sites.

"There are certainly mosquitoes that breed in backyards in what we call cryptic breeding sites," Dr Lindsay said.

"It might be little saucers or a drip tray under a pot plant that holds water for a few days or pet bowls where mosquitoes lay their eggs.

"There are a whole range of backyard breeding sites that people can manage by tipping out the water or putting away rubbish and plastic containers that might be lying around collecting water from rain or sprinklers."

When it comes to natural breeding sites like wetlands and salt marshes, the public is reliant on local government efforts to tackle mosquitoes.

But Dr Lindsay said being aware of the risks of being in mosquito-prone areas and taking personal protective measures could be effective.

"Wearing appropriate long, loose-fitting clothing and using personal repellents so they don't getting bitten by those mosquitoes — it's surprising how effective that can be," he said.

"You can reduce the number of bites very considerably."