National's flagship welfare reforms have been found to unfairly discriminate against 43,000 solo mums and dads.
In a report just tabled in Parliament, Attorney-General Chris Finlayson says the reforms breach the Bill of Rights Act on three grounds by discriminating on the basis of sex and family and marital status.
He finds the breaches cannot be justified under the Act.
Social Development Minister Paula Bennett and Prime Minister John Key yesterday announced wide-ranging welfare reforms that will introduce work tests for sole parent domestic purposes beneficiaries whose youngest child is six or over.
They will be required to be available to work for 15 hours a week from September 27 and will lose half their benefit if they do not take reasonable offers of employment or refuse to try and find a part-time job.
There are 43,000 DPB beneficiaries in the category affected by the change, which is in the Social Assistance (Future Focus) Bill expected to have its first reading in the next fortnight.
As Attorney-General, Mr Finlayson, a minister in the National Cabinet, is responsible for reviewing legislation to determine whether it conforms with the Bill of Rights Act.
A finding that it breaches the Act does not mean the legislation cannot be passed by Parliament.
Labour deputy leader Annette King said the findings were an "embarrassing blow" to Ms Bennett.
She also questioned why the report was tabled the day after the welfare bill. Normally, Bill of Rights Act reports are tabled at the same time as the legislation they relate to.
"Despite legal advice alerting the Government of major flaws in their proposal from a senior minister, John Key and Paula Bennett went ahead with their dog whistle that the unemployed don't want to work.
"Paula Bennett has been exposed. She cares more about looking tough than addressing the real issues facing those on benefits.
"Surely these concerns were raised at Cabinet this week, so why didn't we hear anything from Paula Bennett or John Key on this yesterday? Did the Government deliberately hold back this information?"
Mr Finlayson says the DPB reforms discriminate on the grounds of sex as they place additional obligations and sanctions on widowed men with children compared to widowed women.
Widowed men with children cannot get the widows benefit (WB) - which will not be work-tested - but can get the domestic purposes benefit-solo parent (DPB-SP), which will come under the new regime.
"The introduction of the part-time work test for the DPB-SP for people caring for children over the age of six, but not the WB, means that widowers are subject to additional obligations and associated sanctions. This is a distinction based on sex," Mr Finlayson finds.
The distinction between DPB recipients with children over six and women on the widow's benefit also discriminated on the basis of marital status as solo parents who had always been single or lost their partner through divorce or separation faced work tests, but not those who were widowed.
There was also discrimination on the basis of family status as women on the domestic purposes benefit-women alone did not face work tests, while those with children over six did.
Mr Finlayson finds the discrimination cannot be justified under provisions of the Act which allow reasonable limits on particular rights or freedoms if they serve an important and significant objective' and there is a rational and proportionate' connection between the limitation and the objective.
"The stated objective of the [welfare] bill as a whole is to create a fairer benefit system with an unrelenting focus on beneficiaries entering or returning to employment.
"While this is an important and significant objective, the different treatment of people on the DPB-SP compared to women on the WB and DPB-WA does not serve this objective because it does not create a fairer benefit system or encourage beneficiaries to enter or return to employment."
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