The man accused of killing his stepdaughter has been found not guilty in a majority verdict.

The 12 jurors told the High Court trial in Auckland have found Michael Joseph Martin, 25, not guilty of murder, not guilty of manslaughter, and not guilty of ill treatment of a child.

The Crown said Martin struck Leilani Mary-Jane Lotonu'u's stomach with a blow so severe it ruptured an internal organ and a resulting infection proved fatal.

The defence argued Martin was innocent and Leilani's mother Amy Lorigan must have been responsible.