Parliament has unanimously passed a bill that extends paid parental leave.

It will increase from the current 18 weeks to 22 weeks from July 1 next year and to 26 weeks from July 1, 2020, and it was the first government bill to be passed since the election.

"Let's get this job done," the minister in charge of the bill, Iain Lees- Galloway, told parliament.

"Pass this bill today, give parents the 26 weeks paid parental leave they have been demanding for so long."

He said the most important thing about the bill was that it would make "a real and tangible difference", especially for families on low and moderate incomes.

National supported the bill.

"It's entirely consistent without our approach, we campaigned on increasing paid parental leave to 22 weeks," Amy Adams said.

"But we continue to want to see full flexibility."

Ms Adams was referring to National's unsuccessful attempts to change the bill during its previous stages so that both parents could take paid parental leave at the same time.

The government didn't want that put into the bill but has said it will work with National to include it through another bill next year.