Fire crews are bracing for worsening conditions on Saturday evening and Sunday morning as temperatures remain high across the state and wind speeds increase.

On Saturday afternoon, there were six grass fires burning, although none of them were classified as major emergencies.

Craig Lapsley, emergency management commissioner, said overnight temperatures in the high 20s would create challenging conditions if more fires start in the late afternoon.

"If we have fires running, and we haven't got any [serious ones], it offers us a lot more challenges in a control sense if we have hot overnight temperatures and stronger winds," he told media.