Crews injured and homes lost as NSW burns

NSW Rural Fire Service commissioner Shane Fitzsimmons on Thursday said two male firefighters - aged 36 and 56 - had been airlifted to a burns hospital with serious injuries while a 28-year-old female was transported by road to hospital.

A further two firies were treated by paramedics for smoke inhalation after fighting the Green Wattle Creek blaze west of Bargo.

The commissioner said the crew was in one of many dozens of trucks in the area working to protect homes on Thursday when they were enveloped by fire.

"Those injuries are reported to three people in particular - two males with face and airway burns and some other burns to different parts of the body such as arms, elbow, upper chest and a leg," Mr Fitzsimmons told reporters in Sydney.

"The third person, she is suffering some smoke inhalation and minor burns."

The RFS chief said the crew members were alert and conscious "however given the serious potential for airway burns the advice is medically they'll be intubated".

NSW Ambulance Inspector John Brotherhood said the situation was "absolutely horrific".

"It really proves how dangerous these fires are, how quickly things can change," he said in a statement.

Mr Fitzsimmons said there were reports of "many structures and many buildings being impacted including some homes".

"There's everything from people's homes, people's businesses, there are poultry farming operations ... there are lots of buildings, including people's homes and livelihoods that have been impacted by this," the RFS commissioner said.

'In the vicinity of dozens" of buildings had been destroyed, he added.

The ABC reports at least six homes have been lost but AAP has been told more than 20 homes may have been destroyed in and around the village of Balmoral.

The Green Wattle Creek blaze was one of two fires at emergency warning level on Thursday evening.

Residents in Bargo, Yanderra, and Balmoral as well as Pheasants Nest, Buxton, Couridjah, Thirlmere and Tahmoor were told it was too late to leave.

"Seek shelter as the fire approaches," the RFS warned at 3.30pm.

An evacuation centre at Picton Bowling Club - which has a capacity of 300 people - is completely full.

Wollondilly Shire Council mayor Matthew Deeth says the club's car park is "pretty much dogs and cats as far as the eye can see".

"We're a semi-rural community so we have a lot of livestock that has been needed to be moved quite quickly," Mr Deeth told AAP, adding residents were very anxious.

"There are a lot of people feeling concerned about their properties, we've had quite a number of properties that have been lost today and there's been about six properties lost previously."

A week-long state of emergency has been declared for all of NSW.

A total fire ban is in place across the entire state and there's extreme fire danger in the Illawarra-Shoalhaven, southern ranges and Greater Sydney areas.

Australian Associated Press