Senior Labour MP Trevor Mallard says he believes if the people involved in a fatal curse lifting ceremony were not Maori, they would be sent to prison.
Community-based sentences were imposed in the High Court in Wellington last week on five people found guilty of the manslaughter of family member Janet Moses in Wainuiomata.
Ms Moses drowned in 2007 after water was forced into her eyes and down her throat by family members who thought she had a makutu, or Maori curse.
Mr Mallard, MP for Hutt South, which takes in the suburb, has written on the Labour Party's Red Alert website saying that the five were not sent to prison because they were Maori, and that such a decision is not right.
He told Morning Report on Monday that he believes Justice Simon France got it wrong.
"It is a very unusual set of circumstances and I think, in this case, the judge got it wrong," he said.
"I think there is a lot of sympathy for the individuals involved. They did get caught up in some sort of hysteria. They were sleep-deprived.
"But there's just not an acceptance either from the vast majority of Maori or pakeha people that you can effectively torture someone for well over a day ... causing death and there not be a jail sentence."
Not a racial issue - PM
Prime Minister John Key said it is generally bad practice for politicians to comment on sentencing, but he wanted to respond to Mr Mallard's comments regarding the Moses case.
Mr Key said it is his view that the intent of those convicted was not to kill Ms Moses, and he believes it is not a racial issue.
Justice Minister Simon Power said he does not comment on sentences as has respect for the separation of the judiciary and the executive. He advised other MPs to do the same.
The Crown has said it will not appeal against the sentences.
The Maori Party said sentences are a matter for the courts to determine, while the Green Party believed the judge's ruling should be respected.
The Sensible Sentencing Trust said it is surprised at the frankness of Mr Mallard's comments on the controversial court case. Spokesperson Garth McVicar said he completely agreed with the view unexpectedly expressed by Mr Mallard.
Maori lawyer Moana Jackson said he is certain Mr Mallard's comments are just politicking. He believed the MP's views are ridiculous and any judge would make an equally reasonable decision in similar circumstances.