The man who died after a raft he was in overturned on the Shotover River has been named as 31-year-old Joshua Paroci.
Mr Paroci, of New South Wales, Australia, fell into the river with other occupants of a Queenstown Rafting and Challenge Rafting trip on the "Toilet" rapid on Saturday.
While he was being pulled to safety, he lost his grip on the rope and was swept into the next rapid.
The safety kayaker helped him navigate the rapid, but after making it to shore the man became unresponsive, the companies say.
He was unable to be resuscitated despite getting CPR and treatment from a paramedic.
The companies, who work together offering rafting trips, are assisting Maritime New Zealand with its investigation.
Police offered their condolences to Mr Paroci's family and friends and are making inquiries into his death on behalf of the Coroner.
Queenstown Rafting general manager Luke Taylor says his staff have been left devastated by the death.
"Our hearts go out to our guests and the families of those involved in this. Both our companies wish to offer the group our sincere condolences and ongoing support."
Just two months ago, Queenstown Rafting lost one of its guides on the same stretch of river.