Australians born after 1965 will have to work until they are 70 before they are eligible for the age pension under changes announced by Joe Hockey, while the Treasurer has also warned there is "no such thing" as a free visit to a doctor or free welfare.

On Friday, Mr Hockey said nobody currently on the pension would be hit by the rise in the pension age in the federal budget but the change could struggle to pass through the Senate as Labor families spokeswoman Jenny Macklin accused Prime Minister Tony Abbott of breaking a pre-election promise not to touch pensions.

Misses the retirement cut: Joe Hockey. Credit:Bloomberg

In what is expected to be his final major speech before handing down his first federal budget on May 13, Mr Hockey said the Coalition would deliver a document that is "not going to be an austerity budget, but it is going to be a prudent budget", which would prepare Australia for the demographic challenges posed by an ageing population.

"What we are going to do is to deliver a fairer system for the aged pension that is going to focus on the sustainability of the system with a reasonable quality of life," he said. "The aged pension expenditure today is currently more than we spend on defence.