Wellington, Jan 24 (DPA) Fifteen pilot whales died Sunday after a mass stranding on an inlet at Port Levy, 45 km south-east of Christchurch, on New Zealand's South Island.

Staff from the Department of Conservation and local volunteers managed to return six to the water and they were followed by another 50, Radio New Zealand reported.

Kimberly Muncaster, chief executive of the Project Jonah organisation, said it was believed to be the first mass stranding in the region in 100 years and the whales may have become disoriented in the shallow harbour while searching for food.