Former prime minister Malcolm Turnbull has lobbed a stinging critique of his successor Scott Morrison's handling of the bushfire crisis, saying his conduct is "not consistent with the way in which [a] prime minister would or should act."

Key points: Malcolm Turnbull said he could not understand Scott Morrison's actions during the bushfire crisis

Malcolm Turnbull said he could not understand Scott Morrison's actions during the bushfire crisis The former prime minister also took aim at world leaders such as Donald Trump for failing to act on climate change

The former prime minister also took aim at world leaders such as Donald Trump for failing to act on climate change Mr Turnbull has previously criticised former prime ministers for their running commentary on politics

In two wide-ranging interviews with the BBC, Mr Turnbull took aim at US President Donald Trump — labelling him the "world's greatest climate change denier" — and said Australia needed to do more to cut its carbon emissions and be a world leader on tackling the environmental threat posed by climate change.

But his comments about his successor have raised eyebrows in Canberra, as he argued Scott Morrison's leadership during the bushfire emergency had been lacking.

The former prime minister said he had known Mr Morrison for two decades, but could not explain his conduct.

"Everybody knew we're in a very dry time, and as a consequence, the fire season was likely to be very bad," Mr Turnbull said.

"So rather than doing what a leader should do, and preparing people for that, he downplayed it and then of course chose to go away on holiday in Hawaii at the peak of the crisis.

"It's just not consistent with the way in which [a] prime minister would or should act."

Upon leaving politics, Mr Turnbull had criticised interjections on party policy and political performance by former prime ministers Tony Abbott and Kevin Rudd, labelling them "miserable ghosts".

Malcolm Turnbull said he could not explain Scott Morrison's behaviour during the fire emergency. ( ABC News: Matt Roberts )

His autobiography is due to be released in late April.

Mr Turnbull urged the Federal Government to do more to tackle climate change, accusing right-wing think tanks and Rupert Murdoch's media empire of fuelling "climate denialism".

"If a country like Australia is not prepared to grapple with this issue seriously, itself being in the front line of the consequences and being an advanced, prosperous, technologically sophisticated country with the means to do so, then why would other countries take the issue as seriously as they should?" he told the BBC.

In response, senior Government sources pointed to comments Mr Turnbull made in March 2018 after fires on the New South Wales south coast, where he was questioned as to the role of climate change on bushfires.

"You can't attribute any particular event, whether it's a flood or fire or a drought or a storm, to climate change," he said at the time.

"We are the land of droughts and flooding rains, we're the land of bushfires."