Prime Minister Tony Abbott has dismissed a UN assessment that the New South Wales fires are linked to climate change, accusing a senior UN official of "talking through her hat".

Earlier this week, the executive secretary of the UN Framework Convention on Climate Change, Christiana Figueres, said the fires proved the world is "already paying the price of carbon".

She also criticised the Abbott Government's direct action plan to tackle climate change as being potentially "much more expensive" than the carbon pricing scheme that it is moving to dump.

But Mr Abbott argues that "fire is a part of the Australian experience" and not linked to climate change.

"The official in question is talking through her hat," he told 3AW.

"Climate change is real, as I've often said, and we should take strong action against it.

"But these fires are certainly not a function of climate change - they're just a function of life in Australia."

The Prime Minister fought the fires himself last Saturday night with his local Davidson Rural Fire Service (RFS) brigade in the Bilpin area of the Blue Mountains.

"We lit up various back-burns," he said explaining what his work with the RFS involves.

"You get out the drip torch, you light up along a fire trail or a cleared area, you get the fire going then you watch for a while to make sure it's behaving itself, then you wait to get re-tasked."

Greens leader Senator Christine Milne took Mr Abbott to task on Twitter, posting:

PM Abbott insulting .@cfigueres is symptomatic of his climate denial and real losers are those who will suffer from extreme fires, floods. — Christine Milne (@senatormilne) October 23, 2013

Later, she added:

PM Abbott has no regard for evidence based science and prefers ideology. What is future of science in Australia? — Christine Milne (@senatormilne) October 23, 2013

Firefighter Abbott never feared for his safety

Mr Abbott conceded his personal security detail is "not very" happy about his work with the brigade but he says he will continue to volunteer with the RFS despite the dangers.

"I love my service with the brigade," he said.

"It helps to keep me grounded, quite apart from being an important form of community service.

"Obviously, my time is much more limited but yes, from time to time I will do my best to turn out with the brigade."

Prime Minister Tony Abbott says the bushfires currently facing NSW are "part of the Australian experience". ( AAP: Dan Himbrechts )

He said he has explained to his security personnel that the rural firefighters do not take "silly risks" and that they are "well-trained, well-equipped and well supervised".

"The risks are all well and truly considered and they're taken for good reason," he said.

"I think the risks are well within the bounds of what's acceptable.

"Even as a prime minister, you've got to be a human being first.

"It is a normal part of a normal Australian life to serve in various community organisations ... and I will do my best to continue to be a citizen as well as a prime minister."

Mr Abbott said his "hairiest" day with the RFS was on Boxing Day in 2001, but that he never feared his life was in danger.