In an interview with CNN's Christiane Amanpour on Monday, the head of the UN's climate change negotiations, Christiana Figueres, said there was a clear link between climate change and bushfires such as those raging in New South Wales.

She noted that the World Meteorological Organisation had not yet established a direct link between the NSW fires and climate change.

"But what is absolutely clear is the science is telling us that there are increasing heat waves in Asia, Europe, and Australia; that these will continue; that they will continue in their intensity and in their frequency," Ms Figueres said.

The highly unusual intervention by a senior UN official in a domestic climate policy debate comes three weeks before the next major round of UN-sponsored talks in Warsaw. The negotiations are aiming to reach a global climate treaty by 2015 that would take effect by 2020.

Ms Figueres described the NSW fires as an ''example of what we may be looking at unless we take actually vigorous action''.

The UN negotiator said the new Abbott government had chosen a more difficult and expensive path to emissions reduction than the previous Gillard government – noting that the Coalition had not stepped away from Australia's commitment to reduce its emissions by 5 per cent by 2020.

''The road that they are choosing to get to the same target that the previous government had could be much more expensive for them and for the population,'' Ms Figueres said.

This comes as Environment Minister Greg Hunt announced that the government could bypass the Senate and introduce its ''direct action'' carbon abatement policy through regulation.

The UN adviser said the Abbott government would not only pay a high political price but a ''very high financial price'' for stepping away from a price on carbon.

''What we need to do is put a price on carbon so that we don't have to continue to pay the price of carbon,'' she said.

Last week, the Australian Greens were criticised for using the NSW fires to attack the Coalition's plan to scrap the carbon tax as homes were lost and a man was killed.

On Monday, Mr Hunt would not be drawn on links between climate change and the NSW fires.

''There are 2000-odd firefighters in the field as we speak, there have been over 200 homes lost and of course a terrible tragedy on the Central Coast,'' he told reporters in Canberra.

''No one, no one should be politicising these bushfires.''

Labor leader Bill Shorten said it was not the right time to debate possible links between the bushfires and climate change.

When asked on Monday if climate change made disastrous events such as the NSW fires more likely, NSW Premier Barry O'Farrell replied: ''Well, clearly, I think that's the science.''

He told the ABC's 7.30 that his job was to translate science into practical action.

''I understand that if you're planning new developments, if you're planning greenfield sites, you can ensure whether for flood damage or for fire damage, you build in a certain way,'' Mr O'Farrell said.

He said it was difficult to ''retro-fit'' already established communities such as the Blue Mountains.

NSW Nationals senator John Williams weighed into the fires debate on Tuesday, arguing that fuel levels had not been adequately managed ahead of the Blue Mountains fires.

Senator Williams told Fairfax Media's Breaking Politics program that more hazard reduction was needed during cooler months and that land should not be ''locked up''.

''If we don't manage our environment, it will simply burn,'' he said.

While his Coalition colleague Greg Hunt has argued that the fires should not be politicised, Senator Williams criticised the former Labor government for ''locking up'' national parks - noting that former environment minister Tony Burke had rejected the Victorian governments bid to have cattle graze in the state's Alpine National Park.

''Locking up country and leaving it is an equation for savage bush fires,'' he said.