The eastern state of Victoria has faced extreme fire conditions in the past week, with numerous blazes forcing evacuations in dozens of rural communities.
The largest fire has now burnt 74,000 hectares (183,000 acres) of the Grampians National Park, 240 kilometres (150 miles) west of Melbourne, state control centre spokesman Luke Hegarty said.
"We're talking about the fire that's roughly the size of Singapore," he told Australian national broadcaster ABC.
Fire conditions were easing but it would still take time to control the Grampians blaze, which has a perimeter of more than 360 kilometres, he said.
"That means that we need to have walked or driven or flown the entire fire perimeter to be certain that we've got it under control, and that's no easy task."
No deaths have been reported nor homes lost, authorities said.
