The fire danger remains high across most of the state, including the South West and Wimmera regions, where 600 firefighters are battling two emergency level blazes.

The warning comes as stormy conditions temperatures are expected to soar into the 40s today for much of the state.

At least three fires are burning in the Grampians National Park, about 270km west of Melbourne.

VicEmergency has issued a “leave immediately” message for people living in Mirranatwa, a small area on the eastern side of the national park.

“Leaving immediately is the safest option, before conditions become too dangerous. Emergency services may not be able to help you if you decide to stay,” the warning said.

The bushfire is travelling from the national park in a southerly direction and has crossed Red Hills Road and is heading towards Jensens Road.

A watch and act message remains active for Cavendish, Mona Park, Mooralla, Rocklands and Woohlpooer.

Residents in the Victoria Valley are also being urged to prepare to leave, as winds from north increase the risk in the area.

“The situation can change at any time. You must monitor conditions and be ready to act,” the warning said.

Smoke and ash from bushfires and burning operations have also prompted an air quality warning for the region.

The warning remains current for Coleraine, Hamilton, Penshurst, Dunkeld and Glenthompson.

Meanwhile, over the weekend, more than 100 firefighters and incident management team personnel arrived in Victoria to assist with the ongoing fire response.

Fire crews are also battling another out-of-control blaze, about 178km west of the Grampians National Park.

The bushfire is travelling from Little Desert in a westerly direction towards Kaniva-Edenhope Road.

Fire Forest Management Victoria (FFMV) chief officer Chris Hardman said the fire rapidly spread into agricultural land, but there had not been any reports of further property loss.

“It is too late to leave the area safely so you must take shelter now,” the warning said.

“You are in danger and need to act immediately to survive. The safest option is to take shelter indoors immediately. It is too late to leave.”

The Henty Highway is closed between Horsham and Cavendish.

The Hamilton Emergency Relief Centre at Performing Arts Centre will be open from 9am-7pm.

Lightning sparks new blazes 

Authorities are also fighting to contain four separate fires sparked by dry lightning in the Great Otways National Park overnight.

Hardman said the out-of-control blazes were located in “remote and difficult terrain” and travelling in a south-easterly direction from Hordern Vale and Cape Horn.

“No amount of rain will catch up on the shortfall of rain we’ve had since the beginning of spring,” Hardman said.

The Otways fires remain at a watch and act level, with residents in Aire Valley, Apollo Bay, Cape Horn, Cape Otway, Glenaire, Hordern Vale, Killala, urged to monitor changes to conditions.

Dynamic weather conditions continue 

Extreme heatwave conditions are expected to continue for the bulk of the state tomorrow, with temperatures expected to soar into the high 30s to low 40s.

Authorities warned the fire danger will remain high tomorrow

A cool change is expected to develop from the south-west tomorrow morning and reach Melbourne by the afternoon, Bureau of Meteorology senior meteorologist Michael Efron said.

Relief from the heat is not forecast to reach northern parts of Victoria until the early hours of Wednesday.

More showers and storms tomorrow could bring heavy rain, large hail and strong southerly winds to inland parts of the state, which could also elevate fire danger.