The Morrison government has refused a chorus of calls demanding an increase to the unemployment benefit, which has not seen a real increase for a quarter of century.

A Senate committee will on Thursday begin an inquiry into the payment's adequacy.

KPMG economist Dr Brendan Rynne looked at how much Newstart should be set at, including comparing it to the pension, the national minimum wage, and the impact of rent assistance.

"All of those combined came out to a Newstart value of around $370 a week," he told 2GB radio on Monday.

Newstart is currently $277.85 a week; lifting it to $370 a week would put it at half the national minimum wage.

But Liberal MP Andrew Laming says reports like KPMG's are "pretty cheap".

"It's easy to do the economics to prove you need to raise payments," he told ABC News.

Pressed why such a firm would put forward such figures for an increase, Mr Laming said for "cheap headlines".

"They can say anything they want in a free country," he said.

The Queenslander says the rate is "definitely not" preventing job seekers from attending interviews to find work.

"I meet more people without a job than the entire board of the Business Council of Australia does," he said.

"Every week of the year, and I talk to them. And those individuals can get to a job interview with the payments they receive."

KPMG joins the Business Council, former prime minister John Howard, Deloitte, unions, Labor, the Greens and welfare groups in calling for Newstart to be lifted.

When asked how such a broad spectrum of groups could be wrong, Treasurer Josh Frydenberg insisted the government was focused on getting people into employment.

"We've got a disciplined approach across our spending commitments and we're ensuring that that is rolled out in a way that benefits the economy and sends more people into work," he told reporters in Melbourne.

Australian Associated Press