Authorities are monitoring fire threats in two of Victoria’s most popular national park holiday destinations on opposite sides of the state, with tourists and locals in the Grampians and Wilsons Promontory urged to monitor alerts.

Total fire bans have been declared for the Wimmera and South West regions on Saturday, with the Wimmera extreme fire danger rating expanding on Sunday to include the Mallee and central Victoria.

Key said the forecast mid to late-afternoon wind change and potential thunderstorms in the Grampians were concerning, along with the health risks of “sticky” conditions across the state.

“Firefighters have managed to stop the spread of the fire in a sensitive area and will remain on scene,” the Vic Emergency website said.

Forest Fire Management Victoria State Agency Commander Dave Sayce urged everyone to do their part to prevent bushfires.

A cool change is due to sweep through SA and Victoria by Monday, with heatwave conditions forecast to shift into NSW resulting in high fire danger in large parts of the state.