Temperatures are predicted to rise from today in all states except Tasmania, caused by a large high pressure system moving east across the country from Western Australia.
Severe heatwave conditions are first predicted for the western Top End on Tuesday, rising to severe in some parts on Wednesday.
During this time low intensity heatwave conditions are forecast for across the interior of Western Australia, South Australia and extending into south-western NSW and northern Victoria, becoming severe in South Australia and Western Australia.
Darwin will be hit the hardest of all the capital cities receiving temperatures around 35°C until Sunday.
In Sydney temperatures are forecast to reach 33° on Wednesday, peaking at 38° on Friday with temperatures in the high 30s likely in all suburbs.
There is the chance some places, particularly in Sydney's western suburbs, to see their first 40° day since last year.
Temperatures in Brisbane will hit 30° on Wednesday and peak at 34° on Saturday.
Melbourne's weather will reach 31° tomorrow and peak at 34° on Thursday.
Regional areas in both New South Wales and Victoria can expect temperatures in the around 40°.
Canberra residents will experience temperatures between 30° and 33° between Wednesday and Friday.
In Adelaide BoM is forecasting 34° on Tuesday, 38° on Wednesday and 35° on Thursday.
South Australia is on track for its hottest spell since summer and hottest November spell in six years.
Perth is forecast to experience a peak temperature of 35° on Saturday.