The Labour Party is joining the Green Party and promising to repeal what it calls a draconian law if it's elected.
The New Zealand Public Health and Disability Amendment Bill, passed under urgency last year, caps payment to family members caring for a disabled family member at 40 hours a week.
It also enables family carers to be paid less than others and prevents legal action by new claimants.
A petition with hundreds of signatures calling for the repeal of the law was presented to the Green Party on Tuesday afternoon.
Disabled Person's Assembly chief executive Rachel Noble said the law makes people who have a disability feel like objects, not citizens.
Labour's Disability Issues spokesperson Ruth Dyson said the legislation would not last under a Labour government.
She said the legislation only discriminated further against people with disabilities and their families.