One Australian state could sweat through its hottest October day ever as a blistering heatwave breaks records across the country. 

Birdsville, in Queensland, was forecast to reach 46C on Tuesday, which would beat the previous 41.5C record for the state.

It comes after records were smashed across the state on Monday, with Ballera reaching 44.2C, its hottest October day since 1998.

Windorah recorded a new benchmark of 43.2C while  Thargomindah hit 43.1C, its equal hottest day since 1879. 

In South Australia's north, Moomba Airport and Oodnadatta smashed heat records on Monday when they hit 44.1C and 43.5C respectively. 

South Australia, QueenslandNSW, Western Australia and the Northern Territory will swelter through scorching temperatures in the coming days, with the mercury predicted to hit the mid-40s in many outback regions.

Meteorologists predict this could be the hottest October week in nearly two decades in those states. 

Canberra is tipped to reach a top of 30C on Tuesday, while Sydney will experience its hottest day so far this spring on Wednesday.

Large parts of Australia will be blasted with a pre-summer heatwave this week. Pictured in red are the hottest places across the nation on Wednesday

Large parts of Australia will be blasted with a pre-summer heatwave this week. Pictured in red are the hottest places across the nation on Wednesday

Sydney will experience its hottest day so far this spring on Wednesday

Sydney will experience its hottest day so far this spring on Wednesday

Temperatures are forecast to soar to 38C in the CBD and surge into the 40s in the city's west, before the mercury plummets overnight. 

Temperatures will also climb as high as 44C in Bourke, Cobar and Coonamble in north-west NSW in the coming days.

Outback Queensland will also swelter through temperatures 10C above the monthly average for the next three days.

Extensive fire bans remain in place for large parts of Queensland for the next fortnight. 

'In terms of our heatwave warning, they're currently focused on the north-west and the west where that pulse of heat is currently sitting,' Bureau of Meteorology senior forecaster Baden Gilbert told the ABC.

'It's pretty exceptional for this time of year.'

It's a different story across other parts of Australia's south, with rain, storms and cooler temperatures forecast for capital cities Melbourne, Adelaide and Hobart for the rest of the week.

Elsewhere across Australia, a severe weather warning for powerful winds has been issued for southern NSW on Wednesday.

Birdsville in outback Queensland is expected to hit 46C on Tuesday, which will be an October record

Birdsville in outback Queensland is expected to hit 46C on Tuesday, which will be an October record

Regions in the firing line include the Illawarra, South Coast, Snowy Mountains, Central Tablelands, Southern Tablelands, South West Slopes and the ACT.

'A frontal system moving across NSW on Wednesday will lead to a hot and gusty day across much of the state,' the bureau states.

'Strengthening north to north-westerly winds across the elevated topography and in the east during the morning will shift more westerly and extend to the south-east during the afternoon and evening.'

Brisbane will warm up to a top of 35C on Thursday while Perth can expect a mix of sunny and cloudy with temperatures lingering in the low-to-mid 20s.

In the Top End, Darwin will be sunny and humid with daily tops of 35C.

The Bureau of Meteorology's long-range forecast predicts maximum temperatures will be higher than average nationwide over the four months leading up to February next year.  

November is expected to record higher-than-average rainfall across much of northern and eastern Australia.

Through summer, however, only parts of far north Queensland and Western Australia's wheatbelt are expected to record unusually high rainfall.

The NSW coastline is the only part of the country likely to avoid the extreme weather, with moisture from a wet winter expected to moderate maximum temperatures.

Perth

Tuesday: Partly cloudy. Max21

Wednesday: Sunny. Min9 Max22

Thursday: Partly cloudy. Min11 Max21

Friday: Shower or two. Min11 Max20

Adelaide

Tuesday: Rain. Storm. Max23

Wednesday: Possible early storm. Showers. Min13 Max18

Thursday: Partly cloudy. Min11 Max19

Friday: Shower or two. Min10 Max23

Melbourne

Tuesday: Late rain at times. Max20

Wednesday: Possible early storm. Rain.Min16 Max23

Thursday: Cloudy. Min10  Max17

Friday: Cloudy. Min10  Max18

Hobart

Tuesday: Partly cloudy. Max 17

Wednesday: Rain. Min9 Max15

Thursday: Cloudy. Min7Max15

Friday: Cloudy. Min8 Max17

Canberra

Tuesday: Possible shower. Max30

Wednesday: Rain increasing. Windy. Min13 Max30

Thursday: Mostly sunny. Min7 Max23

Friday: Partly cloudy. Min6 Max23

Sydney

Tuesday: Partly cloudy. Max23

Wednesday: Becoming windy. Partly cloudy. Min18 Max38

Thursday: Partly cloudy. Min17 Max23

Friday: Sunny.  Min15 Max25

Brisbane

Tuesday: Sunny. Max30

Wednesday: Cloud clearing. Min19 Max30

Thursday: Partly cloudy. Min19 Max35

Friday: Partly cloudy. Min19 Max29

Darwin

Tuesday: Sunny. Max36

Wednesday: Mostly sunny. Min26 Max35

Thursday: Mostly sunny. Min26 Max35

Friday: Mostly sunny. Min26 Max35