Erratic winds and hot, dry weather are creating "horrendous conditions" for firefighters trying to battle a blaze at Crows Nest on Queensland's Darling Downs that tripled in size over the weekend.

Key points: Only significant rainfall will put the Pechey fire out — without that, the blaze is expected to burn for weeks

Only significant rainfall will put the Pechey fire out — without that, the blaze is expected to burn for weeks The fire tripled in size over the weekend from 4,000 hectares to 13,000 hectares.

The fire tripled in size over the weekend from 4,000 hectares to 13,000 hectares. Over 40 aircraft are helping to battle the blaze as conditions remain extreme

Several homes and sheds near the town have been destroyed by the blaze.

Fire crews have been unable to conduct an assessment of the area and the number of properties destroyed is unknown.

Residents who fled the eastern part of the town late on Monday had been warned the fire was "unpredictable" and "dangerous".

Queensland Fire and Emergency Service (QFES) Acting Commissioner Michael Wassing said only significant rainfall would put the fire out.

Without it, the blaze is expected to burn for weeks.

He said the fire area was difficult to bring under control because many areas leading up to the township were steep and inaccessible.

"The slope increases the speed of the fire as it comes into the township," he said.

The bushfire increased in size from 4,000 hectares to 13,000 hectares over the weekend.

Mr Wassing said five homes were believed to have been burnt in the Pechey area yesterday and many more were under threat on the outskirts of Crows Nest.

Bushfire smoke shrouds Crows Nest near Toowoomba. ( ABC News: David Chen )

No-one has been reported missing.

Mr Wassing said a special taskforce was on standby overnight as the fire advanced towards the town.

"It is a really difficult fire — right from the get-go we knew this fire was going to be challenging and we have seen that with the weather conditions," he said.

Fires continue to burn on Moreton Island where campers have been urged to evacuate. ( ABC News )

QFES Deputy Commissioner Mark Roche said fatigue of firefighters was an issue.

"We know we do have many more days, if not weeks to go. We're planning for not only the fatigue of our firefighters but also the fatigue and management of those interstate firefighters that have come to support us at the moment," he said.

Deputy Commissioner Roche said it was unclear how many structures had been destroyed at Crows Nest as crews had not been able to access the area due to the danger of falling trees.

"There are a lot of trees still burning ... we don't want to put our crews in areas where trees may fall on appliances or across roadways."

About 38 aircraft are helping to battle the blaze today as conditions remain extreme.

However, the 737 aircraft that was being used to drop fire retardant on bushfires is now headed back to New South Wales.

There are currently about 70 fires burning across the state, none at emergency level.

"Some of these fires have been burning since September and every time we get these dry, windy conditions they take another run," Mr Wassing said.

"We have weeks ahead of us and our planning as a resourcing perspective across the state of Queensland is already projecting out to Christmas and into the New Year."

Since a state of emergency was declared in Queensland on November 9, police said they had taken action against 18 people for deliberately lighting fires.

Of those, police said, 10 are juveniles who are being dealt with under the Youth Justice Act.

Meanwhile, campers in the Bulwer area on Moreton Island off Brisbane were issued a "leave now" warning at about 6:00pm on Monday as winds changed and conditions once again became "dangerous and unpredictable".

A helicopter dumps water over the fire near Crows Nest on Monday afternoon. ( ABC News )

The slow-moving dangerous fire was burning close to the southern, northern and eastern side of the township.

The blaze has now returned to advice level.

Deputy Commissioner Roche said back burning being conducted on the island today would largely "tie in the fire".

Meanwhile, 21 firefighters from New Zealand are helping to control a fire at Woodgate south of Bundaberg.