A helicopter and specialist swimming teams were rushed out in the middle of the night to rescue motorists trapped in floodwaters.
Police said despite warnings not to travel due to flooding in the Taieri area south of Dunedin, a group of intoxicated young people became stranded on State Highway 87 and had to call emergency services.
The man who called police was sitting on top of his vehicle, with others trapped inside.
"Rescuers were required to carry out a rescue which, had those involved followed Civil Defence advice, would not have been required," said Otago Coast Area Commander, Inspector Kelvin Lloyd.
"Initially rescuers were unable to reach the group in the atrocious conditions, so a rescue helicopter was required."