A new campaign warning parents not to shake babies has a particular focus on Maori.
A Starship paediatrician, Patrick Kelly, says 20 babies a year are admitted to hospital with serious injuries from shaking.
Four or five will die and the others are likely to have permanent brain damage.
And for every reported incident, Dr Kelly told Waatea News, there may be as many as 150 other cases. The problem, he says, is particularly serious among Maori.
Dr Kelly says mothers need to be wary of leaving their babies in the care of men who have a tendency to lose their tempers.