Police are launching a homicide investigation following the death of a man on Matakana Island.

A post mortem on the 22-year-old man who died on the island on New Year's Day has been completed.

As a result, his death has been upgraded to a homicide investigation, says Acting Detective Senior Sergeant Craig Rawlinson.

"Police will not be releasing cause of death at this time.

"Police will be in a position to release the victim's name in the coming days once all family have been advised."

Officers would like any person who was present at the temporary camping ground on Matakana Point Road on New Year's Eve and New Year's Day to make contact with Tauranga Police on (07) 577 4300.

Alternatively, information can also be left anonymously via Crimestoppers on 0800 555 111.