Thirty-three whales are reportedly stranded near Haast, at the sandbar at the mouth of the Okuru River.
"What a sorry sight - up to thirty three whales lying dead or dying," a Facebook post by Haast - The Last Frontier read.
"One whale is on the south side and every effort is being made to keep it alive until the next tide."
In February last year more than 400 whales were stranded in Golden Bay. Nearly 75 percent of them died.
The largest stranding ever recorded in New Zealand was 1000 pilot whales which beached in the Chatham Islands in 1918, followed by 450 of the same species on Great Barrier Island in 1985.
The Department of Conservation has been contacted for comment.