National is being accused of bullying the Maori Party over its vote on a bill to extend paid parental leave.
On Wednesday night, Labour MP Sue Moroney's bill failed to pass its second reading after National unexpectedly cast the Maori Party's proxy votes against it.
Maori Party co-leader Te Ururoa Flavell had to leave the debating chamber for the birth of his first grandchild. He said his party made an administrative error and on Thursday afternoon got the leave of Parliament to change the votes in favour of the bill.
But Labour's shadow leader of the House, Grant Robertson, said Maori Party MP Pita Sharples went down to the House after the wrong vote was cast to try to change it on Wednesday.
Mr Robertson said senior ministers Anne Tolley and Tony Ryall, as well as whip Jami-Lee Ross, took Dr Sharples out into the lobby and then Dr Sharples left.
"I then went after him to find out what had happened and he said to me that the Government ministers had told him that this was a Budget matter and he could not change that vote to be in favour," Mr Robertson said.
"That's unacceptable. The Maori Party should have been allowed to change its vote last night, and that kind of behaviour from ministers is bullying."
Dr Sharples declined to comment on Thursday.
Mr Flavell said he can't say if it was bullying because he wasn't there, but the matter has now been sorted out.
The Maori Party has consistently supported the bill, which guarantees its passage through Parliament. National intends to veto the bill once it is passed.