NSW Premier Gladys Berejiklian says "there isn't much left" of Balmoral in the NSW Southern Highlands, with the devastating Green Wattle Creek bushfire destroying most of the village.

Key points: Temperatures in NSW are set to drop significantly, leaving firefighters hopeful they can bring some fires under control

Temperatures in NSW are set to drop significantly, leaving firefighters hopeful they can bring some fires under control Several homes were lost on Saturday on a day of carnage across the state

Several homes were lost on Saturday on a day of carnage across the state New South Wales is not expected to receive significant rain for up to a month

Ms Berejiklian said residents were still unable to return to see if anything could be salvaged because of the continued fire danger.

"We have received bad news. There isn't much left [in Balmoral]," Ms Berejiklian said.

"Even if people have lost their properties, they still want to go back to see what's left and if there is anything they can salvage.

"We know that's part of the recovery. We want people to have access to their land, to their property, as soon as they can, but it has to be safe."

The NSW Rural Fire Service said as an early assessment about 20 structures had been destroyed across Balmoral, which is about 120 kilometres south-west of Sydney.

NSW Premier Gladys Berejiklian said "there isn't much left" of Balmoral. ( ABC News )

Elsewhere, two bushfires in the Blue Mountains have joined together and the NSW Rural Fire Service (RFS) is not ruling out the blazes connecting with the huge Gospers Mountain "mega fire".

Commissioner Shane Fitzsimmons said on Sunday morning the fires at Green Wattle Creek and Ruined Castle had joined together.

The two massive blazes now all but encircle Sydney to the west, only separated by a narrow 12km strip north of Katoomba.

Earlier, there had been concerns over a man missing from a remote rural property in Bell and another missing from the Dargan area, both near Lithgow.

The RFS said on Sunday night both men had been accounted for.

Efforts across the state have been bolstered by the Australian Defence Force, with support including airlifting people out of at-risk areas in the South Coast and Blue Mountains on Saturday.

Residents were evacuated from Fishermans Paradise and Sassafras on the South Coast by helicopters operating out of HMAS Albatross naval base at Nowra.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 2 seconds 1 m 2 s RFS forced to retreat while battling Blackheath bushfire

Aircraft are also working to do aerial mapping of the fires and check on homes cut off by the blazes.

The fires at Green Wattle Creek, Ruined Castle and the adjoining Three Mile fire have burned through nearly 1 million hectares alone.

"The Gospers fire is likely to be brought closer and connected with the northern side of the Great Western Highway and the communities of the Blue Mountains region as we work to protect those communities," Commissioner Fitzsimmons said.

The ADF helped evacuate people from areas on the South Coast on Saturday. ( ADF: Kelvin Hockey )

"We need to be reminded that the Creek fire and the Ruined Castle fire, they have already joined up. There is potential for connectedness, but we are not expecting them to join."

The fire at Grose Valley was upgraded to emergency level on Sunday morning but was moved down to watch and act in the afternoon, before returning to emergency around midnight.

Fire crews are looking to make headway in bringing several blazes under control as temperatures ease across New South Wales.

Temperatures were only expected to reach the mid-20s, a drop of as much as 20 degrees Celsius from Saturday in some parts of the state, where catastrophic fire conditions wreaked havoc and saw several properties lost as southerly winds caused unpredictable fire conditions.

Commissioner Fitzsimmons warned people to remain vigilant despite the easing of conditions.

He said he was hopeful fire crews would be able to wrest back some control amid the cooler temperatures and added firefighters had a battle plan ready that included backburning where possible.

"There'll be a whole lot of things," Commissioner Fitzsimmons said on Saturday.

The chimneys were the only thing left standing at a home in McKellars Park. ( ABC News: James Carmody )

"We're looking at trying to consolidate and establish containment lines across as many fire lines as we can.

"We have significant fire spread south of the Bells Line of Road and through the valley system, such as the Grose Valley in the Blue Mountains region.

"There will be a detailed assessment of the potential threat and the likely threat in coming days or weeks to the Blue Mountains region."

Scott Morrison returns from holiday to visit fire services

Prime Minister Scott Morrison is given a tour of the RFS headquarters in Sydney ( AAP Images: Joel Carrett )

Meanwhile, Prime Minister Scott Morrison arrived at RFS headquarters in Sydney to meet with fire commissioners and emergency service personnel for a briefing on the fire situation in NSW.

Mr Morrison conceded he caused "great anxiety in Australia" by taking a family holiday in Hawaii as bushfires burned across the country, saying with the benefit of hindsight he would have made a different decision.

"I get it that people would have been upset to know that I was holidaying with my family while their families were under great stress," Mr Morrison said.

"I am not a trained firefighter nor am I an expert like those in the next room doing an amazing job, but I am comforted by the fact that Australians would like me to be here simply so I can be here alongside them as they go through this terrible time.

"And so to those Australians who [I] … caused upset to … I apologise for that."

Prime Minister Scott Morrison meets with evacuees at Picton Bowling Club. ( ABC News: Sarah Hawke )

Mr Morrison acknowledged firefighters were "fatigued" and people were scared.

"No-one wants to be out there fighting these fires, no-one wants these fires to be happening at this time. They're getting tired and they're getting fatigued," Mr Morrison said.

"I know people are anxious and I know people in some place are rightly fearful of what is literally at their door."

While light rain is forecast in Sydney around Christmas Day, it is feared it will not make an impact and extremely hot conditions will return at the end of the week.

It will likely be a month before significant rain arrives in NSW.

Fires still burning out of control

The Gospers Mountain "mega fire", which burned through 484,000 hectares, was downgraded to watch and act level at 1:15am, while nearby fires at Kerry Ridge and Upper Turon Road at Palmers Oaky were also downgraded.

The Currowan fire on the South Coast was also downgraded to watch and act status.

A property is lost as The Gospers Mountain Fire impacts, at Bilpin on Saturday. ( AAP: Dan Himbrechts )

Saturday saw temperatures north of 40 degrees Celsius and dozens of buildings were destroyed during a disastrous day for the state.

The RFS said 20 buildings, including homes and businesses, had been affected along the Bells Line of Road, stretching from Lithgow to Bilpin.

The home of the Clarence/Dargan's RFS captain was lost.

His wife Susan Alexander said there was nothing her husband could do to save their home.

Susan Alexander says her husband's fire crew could do nothing to save their home. ( ABC News: James Carmody )

"He drove down our driveway and it's all gone. His sheds are melted. It's all gone and we can't get back in to see. It's a bit morbid but I want to go see my home," she said.

Mrs Alexander also criticised the leadership of Mr Morrison.

"I find it appalling what our prime minister has done, his lack of leadership. There's no empathy. Somebody who makes Kevin Rudd and Tony Abbott look good."

Four firefighters were also injured, with one hit by a car on the Bells Line of Road. Paramedics treated the firefighter, who was not seriously injured.