On Wednesday morning AccuWeather predicted Saturday will reach 46 degrees celsius for Maitland, while Weatherzone and the Bureau of Meteorology both predicted 45 degrees.

Sunday is looking no better, with the services predicting between 41 and 45 degrees.

If the predictions are accurate, Saturday would be the hottest day on record, surpassing February 21, 2004, where Tocal and Maitland recorded 44.6 and 44.5 degrees respectively.

Weather service Higgins Storm Chasing described the coming weather pattern as “Hell on Earth in Australia” and warned people to stay safe.

“Over the next four to five days, a low pressure trough is forecast to move slowly though South Australia and VIC before drifting North through New South Wales and Queensland,” the service said.

“This trough is forecast to combine with a ridiculously hot airmass overhead and dry in very dry and hot conditions ahead of it to produce widespread severe to extreme heatwave conditions.”

Last weekend Maitland pushed past 40 degrees prompting Hunter New England Health to release a health warning for vulnerable groups including children, pets and the elderly.

Speaking to Fairfax Media, the Bureau of Meteorology’s senior meteorologist Simon Louis said the formidable forecast was the result of a heat build up in the atmosphere above Central Australia. 

“We’ve had a big, broad blocking weather pattern in the mid-level of the atmosphere that’s prevented cold-front systems moving through from the south,” he said.

“We’ve had heat building up in the interior as a result and, this weekend, a frontal system will push through and drag that heat from the interior right across the state, and the Hunter."

Mr Louis said the pattern, with heatwave weekends followed by cooler weekdays, began in January.

"The record was broken in Williamtown for the average daily maximum [at that time]," he said.

"It was quite significant, the record is now 31.5 degrees, half a degree higher than the previous record of 30.9.

"Cessnock Airport also broke a record for the most January days above 40 degrees, seven. The previous record was five."

Mr Louis said heat spells were often associated with El Niño weather events, but the Earth was currently in a neutral phase.

Instead, the increasing hot weather was the result of the background warming of the planet, which means summers will probably only get hotter.  

“Going forward, the expectation is that these heatwaves are going to get more common and more severe,” he said.