As temperatures continue to soar with heatwave warnings issued over a broad part of the nation, some areas are set to face their hottest day in over half a decade.

Temperatures are set to rise past 40 degrees over more than 3500 kilometres of Australia, extending from Victoria's south to Western Australia's Pilbara district, Weatherzone said.

Although the weather is standard for Australia's north west during this time of year, parts of the south east are on pace to experience their hottest day since the Black Summer bushfires today.

READ MORE: Fresh evacuation orders for dozens of towns ahead of 'catastrophic' fire conditions

Melbourne is expected to hit 43 degrees this afternoon, which would be the city's hottest day in over five years. 

The intense heat will continue with Mildura in Victoria's north west forecast to reach 45 degrees, and Renmark in South Australia slated to hit a scorching 46 degrees.

The extreme weather is set to pose a risk to health and infrastructure across the nation's southeast as people are being urged to take necessary safety measures, as the heat is set to continue throughout the weekend.

The intense, dry, and windy conditions have resulted in catastrophic fire warnings in Victoria's Wimmera, North Central, Northern Country and South West districts.

READ MORE: Health officials urge NSW residents to prepare for weekend heatwave

Extreme fire danger is also forecast in other parts of Victoria, as well as in parts of New South Wales, south and large parts of South Australia. 

Winds may also result in thunderstorms that are likely to produce little to no rain across parts of Victoria on Friday, causing a potential fire risk as they pass through.

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