The National Party is accusing the Prime Minister of insulting parents who don't - or can't - stay home with their new babies for six months.
It comes after Labour blocked a Bill allowing parental leave to be split.
"What a shameful day," National's Nicola Willis said.
Willis will not be lectured about parental leave by this Government.
"I find that insulting, this is 2023," she said.
Insulted because Labour blocked her bid to let parents take paid parental leave at the same time.
"The greatest gift we can give a child is time," said Labour's Anna Lorck.
"I think it's extremely important to give the birthing parent - our mothers - the time they need," said Naisi Chen.
Willis wasn't happy.
"I have birthed four children. I find it insulting for members opposite to imply that women do not know what care arrangements best suit their family."
But deputy Prime Minister Carmel Sepuloni was defending the move.
"Part of the reason it was set at 26 weeks was actually to provide for the six months of breastfeeding that the World Health Organization recommends."
The current entitlements mean parents of new babies are able to take up to 26 weeks of paid leave.
It can be split - but only once. For example, one parent could take 16 weeks, then the other take the remaining 10.
If the second parent wants to take time off at the same time, it can only be for two weeks and unpaid.
National wants to allow parents to divide up that 26 weeks however they please.
"Having that consistent at home presence for the first six months of a baby's life is really important to their emotional as well as their physical development," said Prime Minister Chris Hipkins.
Willis said: "Those of us who have returned to work when our babies are small already feel our heartstrings hurting and to have people at the highest level suggest we haven't done the right thing by our children, that is deeply hurtful."
Amelia Wade Analysis
It looks like Labour's going to campaign on a more generous parental leave policy to go up against National's flexi-26 weeks.
But this was a missed opportunity for the party to look pragmatic and progressive. Instead, it looks paternalistic.
