If you're planning a trip to see in the new year you might want to reconsider your plans due to an "extreme" heatwave that's building across south-east Australia in the coming days, authorities have warned.
The heatwave is already heating up parts of South Australia - where a number of cities will hit 40C or higher today.
Sydney is also beginning to heat up, with the mercury hitting 28C today and the top temperature steadily increasing to 31C on Monday and 35C on Tuesday.
New Year's Eve is being tipped as the real danger day for bushfires, as temperatures are due to soar to 43C in the city's west.
Victoria will also cop hot, dry and windy conditions. In the state's east, three fires are currently burning and it's feared they could expand over the coming days.
Authorities are urging those travelling to regions affected by bushfires to reconsider their plans.
"Given the conditions we'll see over the next few days, it's probably not a good idea to be in the parks or forests camping," Victoria's Emergency Management Commissioner Andrew Crisp told reporters."If you've not already travelled, I would suggest that you rethink your plans over the next few days."
Monday and Tuesday are tipped to be the worst days for bushfires and smoke haze, just as we're welcoming in the new year.
Sky News Meteorologist Rob Sharpe said the "extreme" heatwave is currently lingering over northwestern parts of the country, where the mercury is breaking 45C.
"As we move through the week though, that heat is going to build through southern parts of Australia," he said.
"Initially, winds are not going to be that strong so we're going to see a few regions with severe fire danger on Friday, Saturday and Sunday.
"It's not going to be that dangerous, but it really ramps up at the end of heatwave on Monday."
He said that, on Monday, strong winds will "suddenly" pick up and severe heat will hit Victoria, South Australia, NSW and even Tasmania.
Temperatures are set to hit the 40s on the mainland and the mid-30s in Tasmania.
Mr Sharpe said "dangerous" fire conditions are expected to peak on that day and it's likely there will be smoke haze in Sydney on New Year's Eve.
Two firefighters were killed and as many as 100 houses destroyed when bushfires ripped through NSW on Thursday and Saturday last week.
More than 1700 firefighters were in the field on Christmas Day, slogging away to strengthen containment lines before the dangerous weather arrives.
Firefighters have used milder conditions in recent days to strengthen containment lines.
Fire danger ratings are very high today for the ACT, the greater Hunter, the central and southern ranges, the northern and southern slopes and northwestern NSW.
There is a high fire danger rating from the far South Coast up to Sydney, with a low-moderate danger rating in western parts of the state.
In South Australia, firefighters are working tirelessly today to control the 25,000-hectare blaze burning in Adelaide Hills before temperatures rise to about 40C on Friday.
A heatwave bringing severe to extreme conditions will start moving towards the Australian east coast today, affecting the northern parts of the state.
Adelaide will be untouched by the heatwave today with maximum temperatures forecast at 33C.
Conditions will then be very hot on Friday, with the mercury hitting 39C. The fires have destroyed 84 homes and hundreds of other buildings as well as claiming one life.
A watch and act alert remained on Wednesday evening for the Hollands Creek road and Cudlee Creek area.
-additional reporting AAP