Things got personal tonight between members of Parliament during the debate on whether paid parental leave should be extended to six months.
National MP Maggie Barry let rip during the debate, saying Labour MP Jacinda Ardern was ill-equipped to comment as she didn't have children.
The Opposition side of the house erupted with calls for an apology on what Labour's Trevor Mallard said was a new low in politics.
"How many kids do you have?'' Ms Barry said.
She did not apologise for taking aim at Ms Ardern's lack of children.
Ms Ardern said she was more concerned by the position the National Party were taking on the extension of paid parental leave.
The debate, opened by Labour Party MP Sue Moroney, was punctuated by yells from National's Dr Nick Smith - "show us the money.''
Ms Ardern said the Minister of Women's Affairs Amy Adams was asking New Zealanders if they "preferred coal or children?''
"Stop subsidising heavy polluters and we can back kids. Build one less road of national significance and we can help kids and their families,'' she said.
"This Government has proven that their priority is not children.''
Ms Moroney put forward the bill to extend leave from 14 to 26 weeks by four weeks a year over three years.
It passed its first reading by one vote tonight.
Maggie Barry said National were not arguing against the merits of paid parental leave, but the cost.
National MP Louise Upston said "in planet Labour, money seems to grow on trees.''
Ms Moroney said she wasn't prepared for the "sheer venom'' that came from the National Party.
"The sheer anger led by Dr Nick Smith and carried on by Maggie Barry was something I wasn't prepared for, to me it demonstrated an anger towards working families,'' said Mrs Moroney.
"I thought it was quite ugly, this is coming from a government who were on the wrong side of the class size issue,'' she said.
Ms Moroney said paid parental leave would help parents' work-life balance.
The Green Party supported the policy. Its policy is to have 13 months of paid parental leave.
Ms Moroney had her family members up in the public gallery to support the first reading of her bill.
She said figures from Finance Minister Bill English had been deliberately overestimated.
In April, Mr English said the Government would veto the bill because it would require an extra $500 million in borrowing over the next three to four years.
Ms Moroney obtained Department of Labour advice which showed the estimated cost was $285.6m over three years.
The costings showed that in three years, the full 26 weeks' parental leave would cost $315.6m a year.