The head of the NSW Rural Fire Service has dismissed claims by Nationals MP Barnaby Joyce that a lack of hazard reduction burns, not climate change, is the main culprit for Australia's ongoing bushfire crisis.

Speaking on Channel Seven's Sunrise program on Wednesday morning, Mr Joyce spoke of “green caveats” – the red tape he believes prevented firefighters from conducting hazard reduction burns ahead of the bushfire season.

“I believe, and this is my opinion, there are too many caveats that have been placed on people, let’s call them ‘green caveats’, that impede people’s capacities to fight fires," the former deputy prime minister said.

But RFS Commissioner Shane Fitzsimmons said hazard reduction burning was challenging and the biggest impediment to completing burns was weather.

Mr Fitzsimmons said longer and hotter summers driven by climate change meant there was a "shrinking window of opportunity" for more favourable burning periods.

"Hazard reduction is absolutely an important factor when it comes to fire management and managing fire in the landscape, but it is not the panacea," he told the ABC.

"When you're running fires under severe, extreme or worse conditions, hazard reduction has very little effect at all on fire spread.

"It's only when the conditions back off a bit … that you've actually got some prospect of slowing the fire spread."

Mr Fitzsimmons said the RFS was now achieving up to 90 per cent of its annual burn program.

He defended fire management agencies saying claims by some politicians that "greenies" have disrupted prescribed burning were untrue.

"We are not environmental bastards; we actually work through a sensible, environmental regime," Mr Fitzsimmons said.

"Our priorities are life, property and that environment ranks third," he said.
Remain vigilant

NSW fires crews were gaining control of more of the state's blazes on Wednesday,  while Victorians have been warned to remain vigilant as temperatures rise again.

Temperatures in fire-stricken East Gippsland are forecast to hit 40 degrees on Friday and authorities warn the forecast spells more bad news.

“In terms of weather and fire conditions, again we talk about, now, benign conditions, the fire is suppressed. It is still there,” Emergency Management Commissioner for Victoria Andrew Crisp told reporters on Wednesday.

“It is still tinder-dry in East Gippsland in the northeast of our state. That’s not going to make a difference. It is holding there for the moment,” Mr Crisp said.

In South Australia, deteriorating weather conditions have authorities fearful of another flare-up of the devastating Kangaroo Island bushfire.

NSW faces another day of very high fire danger, with residents in the Central Ranges, North Western and Southern Slopes warned to prepare their properties.

Fire boss rejects Barnaby Joyce bushfire claims as blazes continue_1
Inset: There are fears of a fire flare-up on King Island. Photo: AAP

A wonderful place

Prime Minister Scott Morrison has used a media conference on Kangaroo Island to urge people to holiday in bushfire-affected areas.

"Australia is open, Australia is still a wonderful place to come and bring your family and enjoy your holidays," Mr Morrison said.

"Even here on Kangaroo Island, where a third of the island has obviously been decimated – two-thirds of it is open and ready for business," he added.

"It’s important to keep the local economies vibrant at these times."

-with AAP