Police allege a teenager started a central Queensland bushfire that has destroyed 14 homes, while a fourth person has been confirmed dead in bushfires ravaging New South Wales.

Police say the 16-year-old boy has not been charged with arson, but will be dealt with under the state’s Youth Justice Act. The Cobraball fire, near Yeppoon, is still burning days after it destroyed homes, sheds and cars.

It comes as a man’s body was found in bushland on the southern end of the Kyuna Track at Willawarrin, north-west of Kempsey in the NSW mid-north coast, shortly before midnight on Wednesday. The victim has been identified as 58-year-old Barry Parsons who lived nearby.

Parsons, who lived in a shed, had not been seen since Friday.

The discovery follows the deaths of Julie Fletcher, who died in Johns River on Saturday, and Vivian Chaplain and George Nole of Wytaliba.

Residents of two Queensland towns were told to leave immediately as bushfires in the areas worsened, while NSW authorities warned fire conditions could deteriorate as the weekend approached.

Scores of fires still burning in Queensland

The alerts were issued for Black Snake, near Gympie, and Woodgate, south of Bundaberg, early on Thursday.

Fire conditions in both areas deteriorated overnight and were not expected to improve in the near term, the Queensland Fire and Emergency Services said.

The most significant blazes burning as of midday Thursday are at Noosa North Shore on the Sunshine Coast, Woodgate and Black Snake.

In Black Snake, fire crews were trying to strengthen containment lines while conducting backburning operations ahead of a slow-moving fire heading in a south-easterly direction towards Thornside Road.

A burnt-out car sits on a property after a bushfire swept through the area, in Cooroibah, Queensland, earlier this week. Photograph: Rob Maccoll/EPA

Conditions there were getting worse. “The fire could have a significant impact on the community,” the QFES said, warning that power, water and mobile phone services could be lost.

Residents of Woodgate were told their safest option was to leave immediately as a fire travelled towards Walkers Point Road. “Fire crews will be working to contain the fire, but firefighters may not be able to protect every property,” the QFES said.

An evacuation centre was set up at the Isis Cultural Centre in Childers.

Meanwhile, people in Kinkuna Waters, near Woodgate, were also on alert in case they had to leave suddenly.

On Thursday morning, more than 70 fires were burning across the state after the current crisis erupted a week ago.

While authorities were keeping a close eye on Woodgate, Black Snake and Noosa North Shore on Thursday, firefighters were preparing to make the most of a brief respite in the weather to strengthen containment lines.

On Wednesday residents and holidaymakers clambered on to boats to flee the Noosa North Shore blaze.

The QFES assistant commissioner Tony Johnstone said more than a dozen aircraft were being readied to bring a number of fires under control while moist coastal winds brought short-lived relief on Thursday.

That relief was not expected to last long, with forecasters expecting westerly winds to dominate conditions on Friday as the fire threat intensified. The weather bureau warned the westerlies would push extremely dry air back towards the coastal fringe.

“We would expect to see the maximum temperature quickly return to 4C to 8C above the November average on Friday and into the weekend,” a spokeswoman said.

“When we combine that with the dry air, we expect to see elevated fire dangers once again as we head toward the weekend.”

‘Aggressive fire behaviour’ in NSW

Better weather conditions in NSW have had little effect on aggressive fire behaviour around the state as fatigued firefighters continued to focus on the crisis in the rural north.

Taree, on the mid-north coast of NSW, is blanketed in smoke for yet another day on Thursday. Photograph: Jessica Hromas/The Guardian

More than 55 fires continued to burn around NSW on Thursday morning, with 24 uncontained and eight currently at “watch and act” level.

A total fire ban declared for NSW this week had lapsed. But the Rural Fire Service NSW deputy commissioner Rob Rogers said the passing of Tuesday’s “catastrophic” fire warning day had not made battling blazes any easier.

“We had a better day yesterday – only one fire got to emergency warning – but even in these pretty benign conditions we’re seeing quite a lot of aggressive fire behaviour simply because it’s so dry,” Rogers told the Seven Network.

“Conditions starting to warm up tomorrow, into the weekend and then heating up early next week, a return to more gusty conditions. We’re in for the long haul.”

The RFS confirmed more than 300 homes were destroyed or damaged since Friday, at least 50 of them on Tuesday.

Rogers said fires in the mid-north coast areas including Taree, Port Macquarie, Kempsey and Coffs Harbour were proving hard to control, along with a blaze near Lithgow in the Blue Mountains.

More than 800 firefighters remained in the field to protect properties and establish containment lines ahead of worsening conditions later this week. About 55 schools were due to remain closed in fire-affected areas.

Rogers also defended a Sydney fireworks display on Wednesday night when the statewide total fire ban was in force, saying it had been declared safe by authorities.

A suspected arsonist was reportedly arrested after an army Black Hawk helicopter chased him through Sydney’s Royal national park, but police had yet to confirm the details.

Bushfire brought under control in Western Australia

A bushfire which posed a threat to people and property around Geraldton, north of Perth, has been brought under control.

Emergency WA has downgraded its watch and act warning for the blaze to a bushfire message but says there is still a considerable amount of smoke in the area.

Firefighters remain on the scene mopping up with the fire burning through about 20 hectares of scrub.

The cause has not yet been determined.