Australia's southeast has sweltered through another day of spring heatwave conditions, with temperatures climbing into the mid to high 30s across several states as firefighters battle to bring multiple blazes under control.
The heatwave has spread across the NSW south coast, parts of South Australia and the Northern Territory as well as southeast Queensland.
A severe heatwave warning remained for parts of the NSW south coast with a total fire ban in place on Tuesday and high temperatures expected to continue until Wednesday.
A heatwave is a three-day stretch where both the day-time maximum temperature and the overnight low are significantly above average.
Sydney had its fifth consecutive day of temperatures above 30C, with the mercury hitting 33.6C at Sydney Airport just after midday on Monday.
It was the city's first run of five days over 30C in recorded history.
Almost 30 people attended emergency departments for heat-related medical issues over the past few days, most from the Sydney marathon on Sunday.
The forecast for the city is expected to peak at 34C on Wednesday, with the mercury tipped to rise even higher in the western suburbs.
The Bureau of Meteorology said sections of SA and the lower parts of the NT were also reporting temperatures 10C to 15C above average.
The bureau's Angus Hines said the heat was widespread.
"Roxby Downs, Port Augusta, 38C, 39C. We are rapidly moving towards our first 40C temperature of the season," he said.
Hay, in the NSW Riverina region, reached 37.4C on Monday.
On the NSW south coast, the heat will continue building over the coming days, with a cool change expected late on Wednesday.
The heat wave is expected to shift north later in the week into parts of Queensland, the Northern Territory and Western Australia, driving highs of up to 40C.
NSW Rural Fire Service volunteers worked overnight into Monday to bring a bushfire near Cessnock in the Hunter region under control after it threatened properties at Neath.
Commissioner Rob Rogers said firefighters were still working to contain fires on the state's north coast as temperatures increased and conditions worsened.
"The difficulty is that there is quite a lot of grass fuel that's carrying the fires and making them burn quicker than you would normally expect and obviously (combined with) that very unseasonably warm weather," he told ABC Radio.
But Mr Rogers said firefighting efforts were boosted by the addition of a Chinook helicopter, delivered in July, which would not have been available this early in the season if authorities had to rely on aircraft contracted from overseas.
In Queensland, firefighters brought a blaze at Emerald in the central highlands under control, while bracing for hotter temperatures later in the week.
Residents living near a fire burning at Beerwah, on the Sunshine Coast, were told to be ready to leave if conditions there deteriorated.
Multiple fire warnings remained in place around the Sunshine Coast.
There were around 20 blazes burning across the state over the weekend.
Several areas of the state are expected to be put under high fire danger warnings, with the south west and south east regions potentially seeing severe fire warnings put in place.
