The Morrison government has repeatedly refused to consider lifting Newstart other than its six-monthly changes linked to the rate of inflation.

This is despite a growing chorus of welfare and business groups, economists, unions and politicians on both sides of the divide - including former prime minister John Howard - calling for a decent increase for the first time in 25 years.

"People on that allowance are experiencing significant stress and issues and that must have health impacts on their wellbeing," Australian Medical Association president Tony Bartone told the National Press Club on Wednesday.

"Clearly, if they are struggling, clearly, if it is insufficient to meet their needs, certainly from a health perspective, it makes sense to increase."

Labor, the Greens, One Nation and Centre Alliance teamed up to pass a Senate motion calling for an immediate increase in Newstart and Youth Allowance on Friday.

Dr Bartone's comments came after Labor accused a government minister of intervening to stop a parliamentary committee calling for a Newstart increase.

Then-social services minister Paul Fletcher asked a bipartisan committee to alter an April report to remove a recommendation to lift unemployment benefits, The Sydney Morning Herald reported on Wednesday.

Labor's social services spokeswoman Linda Burney was aghast.

"That is a very, very dangerous precedent," she told reporters in Canberra.

Ms Burney is working on the terms of reference to ask the Senate's economics committee to examine the rate of Newstart, a push expected to win backing from the Greens.

"I have every confidence that that committee will explore this issue very thoroughly," she said.

The doctoring allegation comes after Prime Minister Scott Morrison warned his backbenchers against publicly speaking out on issues that the coalition did not take to the election, including lifting Newstart.

Liberal MP Russell Broadbent, who chaired that parliamentary committee, is among government backbenchers to have broken ranks by arguing the Newstart allowance is too low.

"It seems almost everybody in this country except Scott Morrison and Josh Frydenberg know that Newstart is inadequate," shadow treasurer Jim Chalmers told reporters.

"The reason why we're calling on the government to review and increase Newstart is because it's necessary to alleviate poverty, to get people in a position to find a job, but also good for the economy."

Liberal National Party senator James McGrath said it was not easy being on Newstart, but the only long-term solution was to generate more jobs.

Australian Associated Press