Tony Abbott's prescription for getting the cost of living down and the government back on track has been rejected by Malcolm Turnbull and queried by the nation's central banker.

Mr Abbott used a Sky News interview and a speech on Thursday to launch a scathing critique of the coalition government's direction.

The former prime minister, ousted by Mr Turnbull in 2015, said the coalition had become "Labor lite" and politics should not be "just a contest of toxic egos or someone's vanity project".

Among the Liberal backbencher's ideas were a call for the renewable energy target to be cut to help with power bills and immigration rates to be reduced to "make housing more affordable".

Reserve Bank governor Philip Lowe told a parliamentary committee hearing on Friday the immigration program was a "source of strength" for the Australian economy.

"I am fond of telling visitors 40 percent of Australians were either born overseas or have a parent who was born overseas," Dr Lowe said.

"To give that advantage up just so we can take some pressure off housing prices, I find that problematic."

Mr Turnbull said immigration - which has also been criticised by Pauline Hanson's One Nation - was a "nation-building exercise".

"It is a question of getting the best and the brightest from the world that will meet the demands of our economy and help grow our economy," Mr Turnbull told 3AW radio.

The prime minister later told reporters during a visit to a microphone factory in Sydney he did not think Australians would be impressed by Mr Abbott's "outburst".

"I'm not going to be distracted by it - it's sad," he said.

The government would not be reviewing the renewable energy target, as it provided certainty for investors and in any case the Senate would not support a change, Mr Turnbull said.

The prime minister backed up his comment with a Facebook video in which he committed the government to working with the states to reduce power prices, and make electricity more reliable while cutting carbon emissions.

A staunch Abbott supporter, Tasmanian Liberal senator Eric Abetz, said the ex-leader's comments should not be seen in the context of a leadership challenge.

Senator Abetz said the government needed to freshen up its "policy narrative", pointing to public concerns over immigration.

"We're having an intake of people into our country in circumstances where some of them have now been on welfare for over 10 years," he told Sky News.

"That is not good for our economic or social wellbeing."

Finance Minister Mathias Cormann said Mr Abbott's commentary was becoming "more and more destructive".

"He is not helping our cause, he is not helping our country, he is not helping himself," Senator Cormann said.

"Much of what he says is either wrong or inconsistent with what he did (in office)."

Labor deputy leader Tanya Plibersek said the most concerning thing about the Liberal infighting was the likelihood of Mr Abbott's ideas being taken up by Mr Turnbull.

"It's not just Tony Abbott's policy agenda - based on past experience tomorrow it'll be Malcolm Turnbull's policy agenda as well," she said.

A veteran Liberal member told AAP: "The more he does this, the clearer the reasons why he is no longer leader."

Mr Abbott told the Nine Network on Friday he was seeking to ensure the government had a clear direction.

"My duty as a former party leader is to try to ensure the party and the government stays on the right track," he said.

"Obviously we've got to have a clear direction and strong purpose for the rest of this term of parliament.

"I'm not in the business of taking pot shots at my colleagues."

Mr Turnbull was the person chosen to lead the Liberal party, he said.

"And obviously I support the leader of the government."