Talking about breaking heat records in Australia this summer is starting to sound like, well, a broken record.

The latest in a series of intense heatwaves is sweeping across the country this week, as a mass of hot air from northwestern Australia spreads slowly towards the nation's southeast.

On Monday, Borrona Downs set a new high minimum temperature record for NSW after dropping to an overnight 'low' of 34.6 degrees. This was also within one degree of Australia's high minimum temperature record of 35.5 degrees, which occurred at Wittenoom in WA and Arkaroola in SA during 2003 and 1982, respectively.

Tuesday was the hottest day on record, for any month, in South Australia's Tarcoola (49.0C) and Port Augusta (48.9C). It was also the hottest January day on record for Hillston in NSW, which reached 46.5 degrees.

Canberra managed to exceed its forecast of 39 degrees on Tuesday, reaching a top of 40.1 degrees. With highs of 40-41 degrees forecast between Wednesday and Friday, the city is on track to experience its first four day spell of days at or above 40 degrees on record, with data available back to 1939.

More maximum temperature records are likely to fall on Wednesday as the hottest part of the air mass lingers over a broad area, stretching from the Western Australia Interior across to the Murray Darling Basin. Tarcoola had already reached 48 degrees by 1:40pm local time on Wednesday, while Ivanhoe in NSW had reached 47.1 degrees by 2pm.

Image: Observed temperatures at 2pm AEST on Wednesday, January 16th.

The intense heat will linger until a cool change sweeps over southern and southeastern Australia between Thursday and Sunday, gradually eroding the hot air mass from the south.

In recent weeks, new maximum temperature records were also set in Western Australia's Marble Bar (49.3C) and Alice Springs (45.6C) amid some of this summer's first intense heatwaves.

The highest temperature on record in Australia was 50.7 degrees at Oodnadatta in South Australia during January 1960.