Police have named the man who went missing after being swept away in the Grey River yesterday.
They have yet to find any trace of Jeremy Charles Brons, 24, of Christchurch, despite another aerial search for him this afternoon.
Police said Mr Brons was the navigator in a four-wheel-drive vehicle, and was swept away while trying to secure a line from the vehicle that was stuck.
His family have been speaking to the police and have asked for privacy at this time.
Combined Four-Wheel-Drive Clubs president Nigel Bannan said members of the 4WD community were hurting over the disappearance - but they had not given up all hope yet.
Mr Bannan said Mr Brons was with an experienced group, who had done the river crossing before.
Police said they would review further search efforts tomorrow morning.