Labour and unions are portraying National's welfare policy as tried and failed but National leader John Key says his party just wants to make a difference.

Mr Key yesterday announced his party's welfare policy and said a government led by him would have "an unrelenting focus" on getting beneficiaries into work.

He said there would be no cuts to benefits and National would not introduce a work-for-the-dole or a community wage scheme.

"Instead we will be going one better and will focus on long-term unemployed by requiring them to get paid work and get off the benefit," he said.

"Within 12 months of taking office, National will require everyone who has been on the dole for more than a year to re-apply for their benefit and undergo a comprehensive work assessment."

Under the benefit policy, solo parents will have to seek part-time work once their youngest child is six.

At present there is no obligation for domestic purpose beneficiaries to seek work.

National will also increase the amount of money beneficiaries can earn without losing any of their benefit -- from $80 to $100.

It will relax the abatement regime for beneficiaries with a part-time job -- beneficiaries lose 70c in every dollar they earn over $80 a week and National will raise that to $100 to encourage them to work.

Social Development Minister Ruth Dyson said it was a case of "back to the past" for National.

"The 1990s is back and today the National Party showed how bereft they really are of new ideas," Ms Dyson said.

The policy would introduce a "work or no benefit" approach, increase bureaucracy and stop progress towards a core benefit.

Punishing beneficiaries would mean their children would suffer the most, while the Government's current policy gave people the support and incentives to work, Ms Dyson said.

The Council of Trade Unions president Helen Kelly said the policy was outdated and lacked respect.

She said people receiving DPB needed it.

"The reality is that people get off the DPB at the earliest opportunity that they can and evidence that people stay on it longer than they need to be simply isn't there."

Mr Key said paid work was the route to independence and well-being for most people and the best way to reduce child poverty,

"Long-term welfare dependency locks people into a life of limited income and limited choices."

He said similar policy had worked in the past.

Another key plank was to introduce more frequent assessments during the first few months a person is on a sickness benefit.

Asked about that on Radio New Zealand, Mr Key said there were about 130,000 people on sickness and invalid benefits but only 5600 had been assessed as being able to work.

"We're really indicating that those people are the ones we are going to encourage to undertake 15 hours part-time work or training or be at least looking for work."

After being on the sickness benefit for a year, a person would be required to visit a designated doctor.

Mr Key said sickness benefits were meant to be temporary and some people on them might need on an invalid's benefit.

Other changes included:

* putting into law inflation adjustments to benefits. This is currently done by convention;

* rejecting the Government's planned new benefit terminology because the intended single core benefit "has ended in a farce";

* requiring the most frequent applicants for benefit advances to attend a budget advisory service at the Government's expense to get qualified advice.

United Future leader Peter Dunne gave the policy cautious support but was concerned it would get "overtaken by the hard-liners, so that the policy becomes too harsh and inflexible as a result".