A second "mega-blaze" formed in New South Wales as severe weather conditions fanned fires in the Snowy Mountains area.

In the East Gippsland and Alpine communities in Victoria and New South Wales, firefighters faced strong, gusty and unpredictable winds as a weather change moved through.

Elsewhere, fires in South Australia and Western Australia were keeping emergency services busy as high temperatures and windy conditions fanned flames.

Look back at how the day unfolded.