Prime Minister Jacinda Ardern says a bill for dedicated paid parental leave for a secondary caregiver - usually the father - could be passed next year.

The Government is currently passing a bill under urgency to extend paid parental leave for the primary caregiver, usually the mother, to 22 weeks from July next year and to 26 weeks from July 2018.

The National Party put up an amendment to make that time flexible, meaning parents could take the some of that time concurrently - but the Government did not support it, saying its bill focused on the primary caregiver.

This morning on Newshub's AM Show, Ardern said she liked the idea of dedicated leave for the secondary caregiver and it had a "really good chance" of Government support, but she wanted it to go through the public scrutiny of a select committee process.

She said it could be added to a bill next year that would make sweeping changes to employment law.

"There's absolutely every chance it could happen next year, but we're just working through it now. "

Issues such as impact on businesses had to be worked through.

She said the provisions in the current bill had already been through select committee scrutiny, but a bill for the secondary caregiver had not.

At a function last week celebrating the current bill, former Labour MP and champion of paid parental leave Sue Moroney pushed for two weeks' dedicated leave for the secondary caregiver.

"Getting everyone in the family that attachment and bonding opportunity would be a wonderful next place to go to."