A fresh lead in a near three-decade long West Coast murder cold case

David Robinson's body was found on a remote beach in 1998 - with a gunshot wound to his head.

Detective Inspector Geoff Baber says a new witness has confirmed a previously unknown sighting of the 25-year-old in Kakapotahi, just before his death.

He says the witness also saw him as a passenger in a green coloured four-by-four vehicle hours later.

Baber says the information is crucial, as Robinson's last movements have never been confirmed until now.