The number of Australians aged over 50 receiving the Newstart unemployment allowance grew by more than 40 per cent between 2010 and last year. This dramatically outweighs the 8 per cent growth in the over 50s general population across the same period.

Treasurer Joe Hockey has confirmed he wants to increase the pension age to 70 from 2035, up from 65.

The collision of these two facts poses long-term challenges to the budget, with the likelihood of tens of thousands more Australians signing up for unemployment payments in their 50s and 60s as they wait to become eligible for the pension.

The data, released by the Department of Human Services to the Greens, reveals nearly 200,000 Australians in their 50s and 60s are on Newstart. The spike is “alarming” given the expected changes to the pension age, says Greens senator Rachel Siewert.

Social Services Minister Kevin Andrews says several factors have contributed to the rapid rise in older people applying for Newstart.

“Labor’s changes to the Parenting Payment … pushed tens of thousands of people onto Newstart Allowance, including some people over the age of 50,” Mr Andrews told Fairfax Media.

And an increase in the pension age for women from 64.5 to 65 from July last year meant more women stayed on Newstart for longer in the second half of last year, he added.

Newstart is available to unemployed Australians aged over 22 who are looking for work and meet an income and asset test. The Abbott government wants to lift the age at which a person can receive Newstart to 25. This change is expected to be confirmed in Tuesday's budget.

The Greens claim Abbott government policies will force people onto unemployment benefits and keep them there.

“We’re now on the verge of a series of cruel budget cuts that have the potential to dump more people onto Newstart,” Senator Siewert said. “Rather than working to address these issues, the government is planning a series of cuts and making people work until they’re 70.”

The Greens support various policy initiatives to address the issue, such as a National Mature Age Employment Plan, reducing barriers for older job seekers and investigating the adequacy of Newstart.

The government data reveals that more than 40 per cent of these older Newstart recipients are staying on the payment for longer than two years, and 20 per cent for more than four years. Figures for the overall Newstart population are only three quarters of that. This supports concerns about the barriers older Australians face when they look for jobs.

Mr Andrews said his government was determined to help all Australians find work, and “mature-age workers” in particular. He mentioned as an example the Coalition’s policy to pay $3250 incentives to employers who hire “mature-age job seekers” who have been on welfare payments for at least six months. The policy begins on July 1.