The Independent Police Conduct Authority's found mistakes by police - in a delayed response when preschoolers were killed in Ruakaka

The Herald's Open Justice reports a woman called police at 6.20am in May last year, saying she was hearing voices and her children were dead.

When Police arrived 77 minutes later, they found the children dead.

The woman was acquitted by reason of insanity.

The IPCA's found staff decided to wait until the on-call rural officer began his 7am shift, not send him immediately.

Police say they've addressed the staff decision-making.