Parts of New South Wales and Queensland face record-breaking heat this week, with some areas under total fire bans and severe fire danger ratings as temperatures push 40C.

On Monday morning north-western NSW had an extreme fire danger rating, with severe ratings and fire bans for the northern slopes, New England, the north coast, far north coast and the greater Hunter.

The rating was very high in the central ranges, also subject to a total fire ban, which meant no fires were allowed out in the open or any activity in the open that caused or was likely to cause a fire. This included general-purpose hot works such as welding or gas cutting.

By 3.30pm on Monday, temperatures had already reached 39C degrees in the NSW town of Moree and 38C degrees at Grafton and Narrabri.

About 40 fires were burning across NSW on Monday, mostly centred in the north-east.

On Sunday a NSW Rural Fire Service spokesman said warm and windy conditions were likely to extend into Tuesday.

“It’s severe all through the north-east, getting up to extreme in the north-western area,” Grace Legge, a Bureau of Meteorology forecaster, said.

“But really the whole entire north-east part from the Greater Hunter to the far north coast are expected to be severe today.

“If records are broken it will be early season records – the warmest we’ve seen it this early in spring.”

Legge said the conditions were due to a warm, dry air mass and high winds affecting northern NSW primarily, but pushing into Queensland. That state’s weather would peak on Tuesday.

On Sunday a meteorologist, Jake Phillips, said the bureau was particularly concerned by conditions to the west of the Great Dividing Range.

“It’s quite unusual to see temperatures this warm,” Phillips said. “In large areas of the state we’re seeing daytime temperatures between 8C and 12C above average for this time of the year, and in some places more.”

The heat was expected to shift further north on Monday, the bureau said.

“Broadly, across that north-eastern quarter of the state [on Monday] we’re looking at a number of places currently forecast to reach early-season [heat] records,” a forecaster, Gabrielle Woodhouse, said.

Queensland’s south-east regions, plus the northern Goldfields, upper Flinders and Cape York Peninsula were under very high or severe fire danger ratings for Monday.

The bureau warned the severe fire dangers forecast for the Darling downs, granite belt, Maranoa and Warrego districts had the potential to see localised extreme conditions in the southern forested areas.

Long-running fire bans remain in place across south-east Queensland and up to Rockhampton and across the central highlands.

Fresh and gusty westerly winds brought hot and dry conditions across the area, with temperatures above 37C degrees recorded in towns including Dalby and Oakey on Monday afternoon.

The temperatures were predicted to soar more than 10C above average: Brisbane faces 36C on Tuesday, the warmest October day since 2005 if it happens.

The conditions would be worse than September, the bureau said, when large bushfires tore through the Scenic Rim and Sunshine Coast. However, a cold front was expected to come through the south-west about midnight on Monday.