Labour will not say if it will adopt the families income package announced in yesterday's Budget if it wins the election.
More than a million people would benefit from the $2 billion in spending which was the centrepiece of the election year budget.
It includes changes to Working for Families tax credits, income tax thresholds and accommodation subsidies - all of which would come into effect on 1 April, 2018.
Labour would not say if it would dump the changes if it won the election, but for now it would vote against the plan.
Its leader, Andrew Little, said it did not help low-income families and was an inadequate election-year bribe by National.
"The plan is too heavily skewed, giving the greatest benefits to the wealthiest families. That's not right.
"We want to have a detailed look at the figures and put our own plan together."
Green Party co-leader James Shaw said the family package was a tax cut in disguise for people who were on higher incomes.
"If they were really serious about long-term disadvantaged families then they would have put the bulk of that investment towards people in lower incomes."
Prime Minister Bill English said the package did add up for low and middle income families.
For example, an Auckland family with three children aged under 13, with a household income of $45,000 would receive an extra $71 a week in tax relief and working for families, as well as an extra $140 a week in accommodation subsidies.
Mr English said it was not an election-year bribe, despite the changes not being due to come in until after the election.
"It's election year and people get to make their choices about that. But actually it's pretty hard to implement all this stuff before 1 April next year."
New Zealand First leader Winston Peters said the budget was woeful, weak, wobbly and bound to fail.
He dismissed the families income package.
"When they realise how small it is against rising costs, 1.3 million families getting $26 dollars - well if you gave them a decent minimum wage like other countries, they'd be on $145 dollars more a week."
The families income package leaves opposition parties in an interesting position.
If they do not accept it within their own spending budget, they would have to tell low-and-middle-income earners that under an alternative government, they would not get the income relief promised by a fourth term National government.