Allan Tull was killed when his helicopter crashed west of Ulladulla about 2pm on Friday while working on the Mount Kingiman blaze which has burned through 1700 hectares as unseasonal fires continued to burn throughout the state.

The experienced pilot was described as "an amazing guy" by a colleague at Sydney Helicopters, where he worked.

"It's a massive shock ... we are absolutely devastated with the loss," the employee told AAP.

The crash appears to have been caused when the water bucket became stuck in trees and pulled the 1994 Kawasaki helicopter down.

Sydney Helicopters said Mr Tull's death will be felt by all in the firefighting community and beyond.

"Tully had a wealth of aerial firefighting experience and his aviation knowledge and skills were of the highest standard, he was regarded as one of the most experienced fire bombing pilots in the industry," chief pilot Mark Harrold said in a statement.

The chopper had been registered to Sydney Helicopters since May 2015, with their website saying the company had provided "many hundreds of hours" of aerial waterbombing to NSW and ACT fire agencies.

"The pilot put his life on the line to protect and keep our community safe and he has paid the ultimate price," local MP Shelley Hancock said.

Emergency Services Minister Troy Grant and Premier Gladys Berejiklian also expressed their sympathies.

Mr Tull was quoted in a 2011 New Zealand Herald article, saying he had fought dangerous fires in Australia for more than a decade.

"They have a lot of accidents there, it's dangerous, hot work," Mr Tull told the Herald.

"But you can't think of any of that stuff, else you wouldn't be able to do it. I just think that when your number is up, it's up."

This week's unseasonal bushfires stretching the length of the NSW coast from the Queensland border to Victoria have also destroyed three homes and 22 outbuildings.

Five major fires on the south coast and to the north were still out of control on Friday evening.

The Rural Fire Service has confirmed the Bemboka fire on the south coast burned down three homes and four outbuildings in the Bega Valley while 11 outbuildings were lost in the Mount Kingiman blaze nearby.

The RFS said favourable conditions on Friday helped firefighters backburn and use other methods to contain the blazes.

But they won't all be under control before Saturday when winds are expected gust up to 40km/h.

A blaze at Salt Ash in Port Stephens had earlier been fanned by northwesterly winds, but was downgraded from watch and act to advice early on Friday evening.

NSW Rural Fire Service inspector Ben Shepherd told AAP it was "burning in heath bush which caused it to flare up quickly".

Two separate blazes in Ellangowan and Ramornie in northern NSW were also downgraded from watch and act warnings to advice alerts.

Australian Associated Press