“Where we already have fires in the landscape, sometimes the winds can be a bit difficult, but equally there is potential for lightning across the state so we might see some new starts.”

Country Fire Authority chief officer Jason Heffernan said the total fire ban had been declared because potential hot and gusty conditions posed a big risk as fires continue to burn across the state.

A heatwave warning for South Australia, NSW, Victoria and Tasmania was issued by the Bureau of Meteorology, with temperatures set to reach the 40s in some parts of the country on Sunday.

Conditions should begin to ease on Monday for South Australia, Tasmania and Victoria, but NSW will have to wait until Tuesday for any relief.

Campers must ensure they put out campfires before leaving the site after firefighters responded to 50 unattended fires this year, Forest Fire Management Victoria commander Dave Sayce said.

“We’re asking people to be a bit more aware and careful as they head to the beach, rivers and lakes.”