Finance Minister Bill English says the Government will veto a Labour Party bill extending paid parental leave.
The bill, in the name of the Labour Party MP Sue Moroney, proposes to increase paid parental leave from the current 14 weeks to 26 weeks by 2014.
Parliament's rules allow the Government to veto any legislation it views as having more than a minor impact on its finances.
The Government says at an extra $150 million a year, extended parental leave would be too expensive.
Labour says that would not be the total cost, as the Government would receive some tax back from the parental leave payments, and it would save on childcare subsidies.
However, Mr English says the Government has been working to maintain entitlements to the likes of paid parental leave - even with an extremely tight budget.
Mr English says it is too soon to be increasing spending in this area.