The bureau's new heatwave alert service points to hot conditions from Tuesday for south-eastern Australia.
An extensive heatwave is sweeping eastwards across Australia, baking inland regions and ensuring the Australian Open Tennis Championships has one of its hottest starts.
Players slugging it out at Melbourne Park can expect a very hot tournament, with temperatures to reach 35 on Monday and 41 on Tuesday, and then 39, 41 and 40 for Wednesday, Thursday and Friday, the bureau said in its Sunday forecast update.
''Every indication is that the heat is likely to linger and there'll be high-20s through the second week'' of the tennis, Sam Brown, a meteorologist with Weatherzone, said.
Sea breezes, though, will mean much of coastal NSW will be spared the worst of the heat sweeping across southern Australia. Sydney will have 25 to 30 degree days until Saturday, the Bureau of Meteorology said.
Fire danger ratings are likely to be very high for the week across south-eastern Australia. (View current fire ratings for Victoria here and for NSW here.)
Regions further west and south, though, will experience much higher maximums. Penrith will get 30 to 34 degrees on Monday and Tuesday before four days of 37 to 39 degrees. Wagga Wagga, which reached 39 degrees on Sunday, can expect the mercury to hit 38-43 degrees from Monday to Saturday.
''The heat is definitely very intense,'' Mr Brown said. ''The slow-moving weather pattern has just allowed that heat to build and build.''
Overnight temperatures won't offer much relief. Minimums in Melbourne won't dip below 22 from Tuesday until Saturday, while Friday's low is unlikely to drop below 28 degrees on current forecasts. Sydney's minimums will be a muggy 19-21 through most of the week.
Inland Victoria will see some very hot conditions in coming days. Shepparton, for instance, will endure five days of 40-plus maximums from Monday, with 44 forecast for Thursday and Friday - more than 14 degrees above the long-term January average for the town.
The latest heatwave began to form in north-western WA early last week. The warmth moved southwards on Saturday, sending temperatures up to the low-40s all the way to Perth. Maximums reached 43.3 degrees in the city on Saturday with the mercury hitting 41 degrees by 9.39 am before the arrival of sea breezes eased temperatures.
While Saturday was Perth's hottest day since Boxing Day 2007, the city sweltered through the night. Weatherzone said the minimum of 29.7 degrees set at 3.12 am beat the warmest overnight low by 0.4 degrees in records going back 110 years.
Adelaide, meanwhile, is bracing for five days of 40-43 degree days from Monday, the bureau said.
Along with the tennis, Melbourne Victory will take on the Western Sydney Wanderers in A-League soccer on Tuesday evening - not far from the Australian Open at Melbourne Park.
For some regions of Australia it will be the second belting of heat this year, after an earlier heatwave broke records at 34 weather stations, including the most at any site with more than 40 years of data – at Narrabri in northern NSW.
It comes after 2013 was declared by the bureau as Australia’s hottest year in more than a century of standardised records, with the background warming from climate change a contributing factor.