A 14-strong team of police officers is investigating how a 5-year-old boy came to suffer life-threatening head injuries at his Christchurch home.

An ambulance was called to the boy's home in the Christchurch suburb of Papanui on Wednesday afternoon..

He remains in a critical condition at Christchurch Hospital.

Police say a scene examination will continue at a Papanui address over the coming days and a number of people who came into contact with the boy are yet to be spoken to by police.