Key Points:

A shooting in Blenheim this morning has turned into a homicide investigation after the victim died in Wairau Hospital.

A Blenheim police spokesman said the shooting happened at the Lone Legion motorcycle gang headquarters in Gascoigne Street, Riversdale.

Blenheim police area commander Inspector Steve Caldwell said police were called about 9am in response to a report of shots being fired during an altercation between two groups of people.

"A 39 year old Blenheim man was shot during this altercation and was taken to Wairau Hospital," Mr Caldwell said..

The man had since died.

"Police have commenced a homicide investigation and further staff have been called in from Nelson to assist with this investigation," he said.

Police want to locate the occupants of a White Mitsubishi Galant hatchback, registration number OT1706, a 1989 model.

"Members of the public are warned not to approach the vehicle, but to call police immediately," Mr Caldwell said.

Earlier Detective Sergeant John Hamilton, of Blenheim, said it appeared the incident happened after a group of people had come to the front of the Lone Legion headquarters.

"There's been some sort of altercation between visitors and people inside the headquarters. A firearm has been used and one man has been shot."

The Lone Legion motorcycle club has been active in Blenheim since the 1970s.