Maori Party co-leader Tariana Turia says police must stop man-handling people in custody.
During the past decade, 27 people have died in custody, almost half of them Maori. Four of every seven deaths where force was used also involved Maori.
Police say they have made changes which have resulted in fewer deaths and better care of people.
But Mrs Turia told Morning Report on Tuesday that police could learn from the control and restraint methods used by mental health workers and is surprised that approach has not been adopted.
Mrs Turia said she is shocked by the figures for Maori, but her concern extends to all those held in police custody.