Claims a young New Zealand mother-of-two died as relatives tried to remove a Maori curse from her are being investigated by police.

A homicide investigation is under way into the death of Janet Moses, 22, at a house at Wainuiomata near Wellington on October 12 as relatives looked on.

Police said it appeared she had drowned. She was found with grazes to her upper arms, forearms and torso.

The Dominion Post reported on Monday that at the time of Ms Moses' death family members had been trying to drive out a makutu (curse).

It quoted a relative as saying that the family believed a curse was put on Ms Moses after a relative stole a taonga (treasure).

Police said she had been dead for about nine hours before they were called and have since interviewed dozens of people in relation to the death.

It was believed Ms Moses drowned in water held in plastic containers in the lounge of the house.

Inquiry head Detective Senior Sergeant Ross Levy refused to comment on the Maori curse theory and said police were trying to establish which individuals were responsible for the death.

He said Ms Moses' paternal family were not involved in the ceremony.

As many as 40 people were at the house during the ceremony and more came and went throughout the day after she died, Mr Levy said.

Anglican Maori Church archdeacon Hone Kaa told the newspaper makutu-lifting ceremonies were often used to cleanse victims.

The curse was believed to have been linked to a relative stealing a taonga.

Dr Kaa said water was often used in such ceremonies, but not the amounts understood to have been involved in Ms Moses' case.

He said lifting curses was a difficult process and was wary of doing it.

In some cases victims needed to be held down by several people as the spirit fought, but he was not familiar with injuries such as scratches and grazes being inflicted.