A Bill to extend paid parental leave from 14 to 26 weeks is expected to pass its first hurdle today amid claims by Labour the Government has deliberately misled the public on the cost to taxpayers.

The Member's Bill by Labour MP Sue Moroney has the numbers to pass because it is backed by National's support partner, United Future leader Peter Dunne.

The Government opposes the Bill and has claimed it would cost up to half a billion dollars over the next three to four years. It plans to use a financial veto to stop the legislation at its final reading.

Moroney today said she had received advice from the Department of Labour given to the Government before it announced plans to use the veto, showing the estimated cost was $285.6m over three years.

It also showed when the scheme was gradually extended to 26 weeks over three years, the final cost would be $315.6m a year, or $145.6m more than the $170m cost of keeping it at 14 weeks in three years time.

''Not only did the Government not do any work on the savings the scheme would make to the early childhood education budget, it inflated the official advice it was given,'' Moroney said.

''I think New Zealand families will be concerned about that.''

Subsidies to childcare centres for under-two-year-olds, along with subsidies for lower-income families, could cost taxpayers up to $588 a week, more than the $475 weekly cost of paid parental leave, she said.

''Wouldn't we be better off funding parents, if they chose to, to stay at home with their very young baby instead of handing this money over to childcare centres for strangers to take care of those babies?''

Labour is expecting another win against the Government today with the support of Dunne, which is the passing of the first reading of MP David Clark's Bill to Mondayise Waitangi and Anzac Day.

Labour is driving hard the message that both Bills are good for families.

Finance Minister Bill English yesterday said the Government was sticking to plans to veto the paid parental leave extension.

''We're spending about $155 million a year now on 14 weeks paid parental leave, that's a scheme we think is very important and that's why we've made sure we've maintained it even though we're short of cash.''

Moroney said Labour hoped pressure from families and evidence supporting the extension would change the Government's mind by the time the Bill got to its final reading.

The changes would align New Zealand with other OECD countries, she said.

Labour understood the importance of being thrifty with taxpayer money, which was why the scheme would be phased in over three years.

- © Fairfax NZ News