Wellington - A man swimming off a popular New Zealand beach was attacked by a shark on Saturday, suffering deep wounds to his body and possible internal injuries, news reports said.

The man was flown to a hospital by helicopter while police cleared beaches on Tasman Bay, located in the north of the South Island, and local radio stations warned people to stay out of the water.

The 47-year-old swimmer reportedly did not see the shark, which attacked him from behind off Kina Beach, about 70 kilometres from the city Nelson. The Nelson hospital said he was in a stable condition.

A Department of Conservation expert said sharks were known to frequent Tasman Bay at this time of the year, the Newstalk ZB radio network reported. (dpa)