The Health Department in the Northern Territory of Australia says the Top End needs to prepare for what it describes as an enormous wave of mosquitoes.
The department says an unusually wet October and very high tides have created perfect breeding conditions for saltmarsh mosquitos.
There was a big hatch of mosquitos in the Top End in September and the department says these insects have now all laid eggs.
Saltmarsh mosquitos can carry the Ross River and Barmah Forest viruses. Because of the hot and humid weather, the ABC reports they can can live up to two weeks longer than usual.
The department has sprayed insecticide around Darwin's northern suburbs.
However, it says mosquito numbers will not begin to drop until November.