Heatwave hits SA and Melbourne

South Australia Country Fire Service volunteers tackle a bushfire near Rockleigh in South Australia.

A total fire ban is in place across South Australia as the state faces extremely hot weather and strong winds.

The state's emergency services are warning people to refrain from any outdoor activities which could start a fire.

Adelaide was forecast to reach 43C yesterday - the hottest day since January 17, when the city sweltered at 43.1C.

Total fire bans were in place for all of the state's 15 fire districts, including the Adelaide metropolitan area.

The Country Fire Service (CFS) on Wednesday contained a bushfire which came close to homes in the Adelaide Hills and destroyed about 1000ha of grassland.

The Bureau of Meteorology said a cool change was not expected across South Australia until late today.

Victorians are also feeling the state's first summer scorcher, with temperatures reaching more than 40C yesterday in some areas.

Melbourne reached 39.9C yesterday afternoon and the temperature will be in the mid-30s today, with low 40s in the state's north.

Melbourne's train network has been an early casualty of the heatwave, with operator Metro cancelling almost 50 services yesterday and today for safety reasons.

- AAP