Treasurer Joe Hockey has a new reason for the Senate to pass his budget: Australians could  live to 150.

The statement was immediately branded his 'Sarah Palin moment', but experts in the field say the notion is not as ridiculous as it seems - although the connection to last year's budget might be a long bow.

According to Mr Hockey, such extraordinary longevity explains why Australians should accept cuts to government benefits and pay a greater share of their health costs.

"The fact we are living longer is great news," Mr Hockey said in his first interview back after the summer holidays.

"It's kind of remarkable that somewhere in the world today, it's highly probable that a child has been born who will live to be 150. That's a long time.

"The question is how we live with dignity and ensure we have a good quality of life the whole way through. This is the conversation we [the government] are going to have with Australia over the next few months."

The comments come ahead of the next intergenerational report, due early this year, which is expected to show that the ageing population will make it difficult for the government to pay for services that Australians have come to expect.

But, the idea of 150 year-old Australians was quickly ridiculed by Labor leader Bill Shorten, who described it as a "brain snap".

"Joe Hockey has been kept in the basement over summer and now he's burst out of the basement," he told reporters in Brisbane.

"He's almost had what I'd call his 'Sarah Palin moment'," said Mr Shorten, referring to the gaffe-prone US conservative. "This proposition to justify his 2014 budget, based on a not-yet born baby's 150th birthday in a century and a half's time, just shows, I suspect, our Treasurer's simply lost the plot."

University of New South Wales faculty of medicine dean Peter Smith said the prospect of people living to 150 while "scary" was a "reasonable assumption".

"It's not science fiction anymore," he said, pointing to advances in stem cell medicine and research into drugs that could improve life expectancy and quality.

Professor Smith also noted that life expectancy for Australians has been climbing dramatically over the past 100 years. According to the Australian Institute of Health and Welfare, a boy born between 2010 and 2012 can expect to live to 80 and a girl can expect to live to 84. This is up from 55 and 59 years respectively in 1910.

The world's oldest person who has had their age officially verified was Frenchwoman Jeanne Calment, who was 122 when she died in 1997.

But Professor Smith said that Australians living well into their next century should not be regarded as "all bad".

"I don't think we're just saying that everyone will retire at 65 and then sit at home until we're 150," he said, arguing that people will be living healthier as well as longer.

"People will work and contribute [to the economy] for longer."

Australian National University professor of ageing and public policy Hal Kendig said that if Australians began to survive to 150, there would be "plenty of time to adapt".

He said that in the meantime, the government should not be looking to GP payments to cut costs, but instead at taxation on superannuation and enabling people to work longer.

In his interview with 3AW, Mr Hockey also declined to comment on a reported split within cabinet over the now dumped $20 cut to the Medicare rebate for short consultations.

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