Half of a pod of sixty-five pilot whales stranded on Farewell Spit in Golden Bay have died.
The surviving 34 are stuck in shallow water, between two and three kilometres offshore.
Department of Conservation (DOC) Golden Bay area manager John Mason said there was nothing that could be done for them, other than to hope they manage to swim away on the next high tide.
"They're in a very remote location and they're in a very dangerous location to try and rescue them because to rescue a whale you have to stay with it until it can swim and to do that the water level is usually between your waste and your chest.
Once you've let the whale go you then have to head back to the beach yourself, which in this case would be two to three kilometres away, so we don't rescue them in those situations.
"All we can do is monitor them. I'm not optimistic that they're going to get back to sea but we certainly wish them well and hope that they make it.''
DOC staff found 21 of the whales late yesterday afternoon. Only one of these was still alive but it was in such bad condition that it had to be euthanised, Mr Mason said.
Staff found the remaining whales when they headed to the area at first light today.
Mass whale strandings are not uncommon at Farewell Spit.
They swim into the relatively shallow water during high tide, but the tide recedes very quickly and they become stuck on the sand, Mr Mason said.
Pilot whales can grow to five metres in length.