Scorching conditions that sparked dozens of bushfire battles in NSW are expected to shift north on Thursday to Queensland.

After days of unseasonable heat and wind gusts, NSW fire crews are hoping for some relief as a cool change moves through.

More than 1000 firefighters battled 73 fires into the night on Wednesday.

At least three threatened homes on Sydney’s western fringe and near the Qld border, with residents told to prepare for fire as blazes burned in nearby bushland.

Firefighters were able to gain the upper hand and slow the spread of the flames with the threat to properties easing by 6pm.

With temperatures set to drop to the low 20s, NSW crews will be hoping for a better day on Thursday.

The state has sweltered for days with maximum temperatures 10-15 degrees above the September average.

Queensland is bracing for peak fire conditions on Thursday, when parts of the state are expected to swelter in temperatures 10 degrees above average.

Fire crews have worked to beat back the blazes and reduce fuel loads ahead of the danger.

Late Wednesday, a pilot survived a terrifying ordeal after his helicopter crashed into a dam while fighting a bushfire west of Brisbane.

The helicopter was collecting water to fight a blaze when the crash happened at a private property at Tarome in the Scenic Rim before 3pm on Wednesday.

The aircraft was hovering close to the dam when it hit the surface and rolled, Queensland Fire and Emergency Services said.

The male pilot escaped the wreckage and swam ashore. He was assessed by paramedics and treated at the scene for minor injuries.

The pilot, believed to be in his 40s, was airlifted to Toowoomba Hospital for further treatment, LifeFlight said.

A helicopter pilot swam to safety after crashing into a dam. Photo: AAP

The Australian Transport Safety Bureau is investigating.

The helicopter was being used by firefighters to battle a blaze at Tregony, which has been burning for several days.

“We’ve got a number of fires that we’ve been working on the last few days,” QFES Commissioner Greg Leach said.

He said particular attention would be paid to a fire at Beerwah on the Sunshine Coast to ensure it remained under control.

“We were able to consolidate the control line last night around the Beerwah fire,” Mr Leach said.

“There was some burning of unburnt fuel within the containment line last night, so that helps to secure that line.

“But of course, anything can happen tomorrow if the wind gets up, so we’ll have lots of crews out on the fire line.”

From midnight on Wednesday, there is a fire ban for residents in the Barcoo Shire Council area in the state’s far west until midnight on Sunday.

The mercury in north-west Queensland is forecast to nudge 40 degrees and the south-east can expect temperatures in the mid to high 30s, with 33 degrees forecast for Brisbane and 36 in Ipswich.

But a cool change will move into the south-east overnight before making its way up the coast for a cooler weekend.