Blistering heat that formed over the Nullarbor at the end of December and continues over parts of inland Australia smashed temperature records and was a "highly significant" event, the Bureau of Meteorology said.
In a special climate statement released late on Monday, the bureau said the latest heatwave, while less extensive and prolonged than the record-breaking hot spell to start 2013, was still a remarkable event.
The report comes just days after the bureau confirmed that last year was Australia’s hottest in more than a century of records, easily beating 2005.
"A major feature of the [latest] heatwave was the very large margin by which some records were broken, particularly in northern New South Wales," the bureau said.
"At Narrabri [in NSW], the 47.8 degrees observed on 3 January surpassed the previous record by 3.6 degrees, the largest such margin at any Australian location with 40 or more years of data.
"The heatwave began on December 27 in eastern WA and spread slowly north and east, setting records at 34 sites where data has been collected for at least 40 years.
Most of those sites were in Queensland and northern NSW. Sydney and Melbourne largely dodged the extreme heat with mostly mild and even cool conditions during the past week, and more such weather is forecast for both cities for the coming week.
Parts of north-western WA, though, are about to be hit by another bout of extreme heat with bureau charts indicating regions may reach 50 degrees on Thursday.
In the past week, Queensland copped some of most scorching heat, with the statewide mean temperature on January 3 shattering the previous record by "an extraordinary 0.75 degrees", the bureau said.
More than 10 per cent of Queensland and almost 15 per cent of NSW had their hottest day on record.Gunnedah Research, in northern NSW, broke its previous temperature record by 2.8 degrees, the largest margin between the first and second-highest readings in any of the 112 primary locations used by the bureau.
During the heatwave, Roma in southern Queensland broke its record high temperature on three separate days - December 29 and 30, and on January 3.
Many other locations endured prolonged hot spells, such as Barcaldine, which averaged 43.2 degree maximums for a week, beating a record of 42.8 degrees set in 1972.
Charleville’s weekly average of 43.4 degree maximums easily exceeded the previous high for the Queensland town of 42.6 degrees set in 2006.
"By [January 5], the most significant heat had retreated to the central and northern interior of Queensland, where the heatwave continues largely unabated at the time of writing," the bureau said in its statement.