Wildfires raging across southwest Australia have killed four people as a blistering heat wave sweeps across the country.

Western Australia state police said on Wednesday that the bodies of four people were found in a rural area north of the town of Esperance. Several fires have been raging in the area since they were sparked by lightning on Sunday.

Police say disaster victim identification officers were flying to the small towns of Salmon Gums and Grass Patch, where the bodies were found.

Firefighters have struggled to contain the blazes as fierce winds and temperatures in the 40s Celsius (more than 100 Fahrenheit) have battered the region over the past several days.

Conditions had improved by Wednesday, with the hot, dry air moving east.