New Zealand’s Department of Conservation on Friday said more than two dozen whales had died in a mass stranding at remote Farewell Spit, the South Island beach that is known as a death trap for whales.

Wildlife rangers found 34 long-finned pilot whales at the beach late on Thursday. Five of the whales were refloated later on Friday at high tide. But another beached whale and another deceased whale were later found a short distance from the site at Triangle Flat on Farewell Spit.

Farewell Spit, a 26 km stretch of sand that protrudes into the sea, has been a frequent site of strandings, although scientists are not very clear as to why this happens.

One theory is that the spit creates a shallow seabed in the bay with extensive, kilometres-wide sand flats. This can confuse whales' sonar navigation systems, according to a BBC report.

Last year, rescuers were able to save 28 long-finned pilot whales of a pod of about 50 who had stranded on the beach, but the rest died.

The worst stranding occurred in February 2017, when almost 700 whales beached, resulting in 250 deaths. The area has seen at least 11 pilot whale strandings in the past 15 years.