The baby boy seriously injured in an incident at a Wairoa house a week ago died overnight at Starship Children's Hospital in Auckland.
The four-month-old child suffered life threatening injuries last Saturday morning.
He was initially treated in Wairoa Hospital, then was flown to Hawke's Bay Hospital later that day and on to Starship last Sunday.
Detective Senior Sergeant Dave Greig from Wairoa police this morning said a port-mortem examination will be conducted in Auckland today.
"The results of that examination will not be known for some time,'' Mr Greig said. "We will be making no further comment on the matter until we have received those post-mortem results,'' he said.