More than 400 whales have stranded on a New Zealand beach and about three quarters of them have died. Authorities have described it as the worst whale stranding ever seen. <br/><br/>Conservation workers and volunteers are hoping to re-float the surviving whales at high tide this morning.<br/><br/>Department of Conservation spokesman Andrew Lamason has said that they were putting sheets and buckets of water on the surviving whales and trying to keep them calm.<br/>