Under proposals announced in the budget, job seekers aged under 30 will be ineligible for payments for six months after applying for benefits. But despite not receiving any money, job seekers will be required to meet the activity requirements for unemployment benefits throughout this period. If they fail to do so, their waiting period will be extended by four weeks.

Job seekers will be required to attend monthly appointments with an employment service provider, and show evidence, such as a job search diary, that they have looked for 40 jobs that month.

Brotherhood of St Laurence executive director Tony Nicholson said there was a cost involved in looking for work and it was ''totally unrealistic'' to expect job seekers to fulfil such requirements at a time when they are without an income.

Mr Nicholson said he was particularly concerned about the impact the change would have on young people who were unable to rely on family support because of family violence or breakdown, or whose families could not afford to support them. ''Those people have no option to return home. Without income, they are destitute, and if you don't have money for food and shelter and transport, it's impossible to look for work.''

The president of the National Welfare Rights Network, Maree O'Halloran, said the ''harsh'' changes placed unemployed young people in an impossible position.

''They will have no money for bus fares, newspapers, phone calls or an internet connection, yet if they don't look for work they risk having their payments suspended for an extra four weeks.

''The government's version of mutual obligation is very one-sided. The more one looks into this policy for people under 30, the more unworkable and unreasonable it appears.''

Labor employment spokesman Brendan O'Connor said the federal government wanted to walk away from its obligations to job seekers.

''Not content with stripping young job seekers of support when they need it most, this heartless government wants to kill off mutual obligation once and for all.

Instead of providing a modest income to job seekers looking for work and completing agreed activities, the government wants out of that compact,'' he said.

A spokeswoman for Social Services Minister Kevin Andrews defended the requirements.

''These expectations are reasonable, and similar to what is currently in place for job seekers on Newstart Allowance or Youth Allowance,'' the spokeswoman said.

A spokesman for Assistant Minister for Employment Luke Hartsuyker said the government was still finalising the details of the activity requirements for job seekers under the arrangements.

The government estimates the changes will provide savings of $1.2 billion over four years.