The last confirmed sighting of Christopher James Bates was 3.50pm on Sunday, 11 February, when he was seen at the Z service station on Tarbert St.
The 22-year-old had been heading to a river to meet a friend.
He has not accessed his bank accounts or used his cellphone since.
Mr Bates was reported missing on Thursday and police last night said they had grave concerns for him.
Police staff and LandSAR volunteers from the Wakatipu and Central Otago took part in today's search, as well as a large group of Mr Bates' family and friends.
A specialist search dog team was also assisting.
Detective Sergeant Cameron described Mr Bates as of slim build, about 180cm tall, with short to medium length brown hair and brown eyes.
He was wearing a grey hoodie, white T-shirt, dark shorts and sneakers.
Police would like to hear from anyone who may have seen Mr Bates recently, or has information about his movements last week.
Anyone with information is asked to call 111.
