The Department of Health has warned a jump in the mosquito population could lead to serious health problems for WA residents.

Recent widespread rainfall and flooding has created ideal conditions for the breeding of mosquitoes and other biting insects, with many river systems throughout the Perth metropolitan and regional areas overflowing due to nearly 300 millimetres of rain dumped over the course of the last week.

When protecting against mosquitos, the most effective and long-lasting repellent formulations are lotions or gels. Natural or organic repellents may not be as effective, or may need to be reapplied more frequently. Credit:James Gathany

Managing Scientist Environmental Health Hazards Dr Michael Lindsay said the increase in insect numbers would lead to a higher chance of contracting a mosquito-borne disease.

"While local government mosquito management programs are in place around WA, it is not realistic or logistically feasible to keep mosquitoes and biting flies below nuisance levels when such vast areas of the State are affected with the recent weather conditions," Dr Lindsay said.