Labour's Māori caucus is backing MP Meka Whaitiri, despite not having seen the report that prompted her sacking as minister after an altercation with her press secretary.
But National said the co-chair of the caucus, Employment Minister Willie Jackson, should be backing employees, not their bosses.
Willie Jackson said he hadn't seen the official report but had heard Ms Whaitiri's side of the story, which he was satisfied with.
"I have access to Meka who breaks it all down for me, and so does the caucus. Look, we support her because she's been an honest and strong advocate for our caucus.''
Mr Jackson said he "prides" himself on his working relationships with staff, as "does Meka''.
National's employment spokeswoman Paula Bennett said she could understand Mr Jackson sticking up for a colleague but as a minister it was his job to uphold the law and speak up for employees.
"There is someone who has been potentially hurt in all of this. He's hearing one side of the story, he's then leaping to their support. It seems Labour is talking a lot about their person who has lost their job and not actually thinking about a victim in this,'' Ms Bennett said.
Parliament went into urgent debate yesterday over the removal of Ms Whaitiri as a minister after National's Amy Adams wrote to the Speaker Trevor Mallard requesting it.
Ms Adams told the House the removal of a minister had to be one of the most serious matters that Parliament might deal with - and there were more questions than answers about why that happened.
"So far we've had nothing. No proper statement of what happened. No proper statement from Ms Whaitiri. We've had no apology to the staff member concerned.
"We have Meka Whaitiri accused of assaulting a staff member, we understand leaving bruising on her. An assault, members of the government if you've forgotten, is a criminal offence," Ms Adams said.
"On what planet is it okay for a member who assaults a staff member to remain as a member of Parliament?" she asked the House.
Mr Jackson told Parliament he stood by the prime minister's decision and what had happened to Ms Whaitiri was tragic and sad.
"As a Māori caucus we stand behind the prime minister, we stand behind Meka Whaitiri, we stand behind the victim if the victim has been hurt," Mr Jackson said.
RNZ revealed last week senior Māori caucus colleagues had met with Prime Minister Jacinda Ardern during the investigation to throw their support behind Ms Whaitiri.
Yesterday Mr Jackson said Ms Ardern had consulted with them throughout the investigation but he said the nature of those discussions were private.
Ms Whaitiri said she was gutted about what had happened, but would not reveal any details of the incident, as a final report was yet to be released.
It could be another fortnight before that happens.