Timu flew out of Dunedin yesterday and was expected to link up with the Sunwolves in Auckland.
Timu (21), the son of All Black and Otago outside back John Timu, has played just three games for Otago since making his debut for the side in 2017.
His season was limited last year because of hamstring issues and he then broke his thumb at training at the start of the Mitre 10 Cup season.
The Sunwolves have injuries in the midfield. Shane Gates was the latest the go down. The centre was stretchered off the field in the match against the Chiefs in Hamilton on Saturday night.
Sunwolves coach Tony Brown made contact with Timu in the past couple of days and offered him a position with the side.
Timu, who went to John McGlashan College and plays for the University club, was training on a week-to-week basis with the Highlanders but had no permanent contract.
He played in two pre-season games for the side but has never played in a competitive Super Rugby match for the Highlanders.
He is contracted to play for Otago this season.
That Timu has been signed reflects the depth issues faced by sides as the overseas player drain takes hold and teams are forced to pick younger players.
Timu becomes the latest Otago and Highlanders-connected player to join the Sunwolves.
The Sunwolves are skippered by former Otago and Highlanders prop Craig Miller.
The other Otago players in the side are first five-eighth Hayden Parker and lock Tom Rowe.
The other former Highlanders in the Japanese-based team are Dan Pryor and Phil Burleigh.
Former Otago coach Cory Brown, the younger brother of Tony, is the assistant coach of the team.
John Timu played 101 games for Otago from 1988 to 1994 and played 50 games for the All Blacks, including 26 tests. He switched to rugby league before the 1995 season and played nine games for the Kiwis.
The Sunwolves play the Blues at North Harbour on Saturday night.