Hundreds of volunteers last night kept a vigil over 120 whales restranded on Farewell Spit near Golden Bay.
Project Jonah and local volunteers were urgently recalled by the Department of Conservation at 5pm when part of a pod that had earlier been refloated, beached themselves again on the low tide.
Emotional scenes were a common sight on the shoreline yesterday as volunteers desperately tried to save the mammals, in a day when:
• Volunteers formed a human chain in the water in a bid to prevent pods returning to shore
• 20 restranded whales were euthanised and Massey University pathologists carried out necropsies on carcasses - which were at risk of exploding in the heat
• 100 whales were successfully refloated on the high tide.
An estimated 300 whales have died to date.
DoC Nelson ranger Kath Inwood said the renewed call for volunteers to Farewell Spit - a three-hour drive from Nelson - had led to calls from across the country from willing helpers.
"I'm getting calls from people in Christchurch and places like that," Inwood said.
"I just had a call from a couple of guys from Napier in the car on their way down because they really want to help. People from Auckland ring up and say 'Can I come and help?'."
She said whale strandings were "so fluid" in that the situation could change at any minute.
Some of the 500 volunteers caring for 100 of the beached whales on Friday had sung to the gentle giants, some of which stretch longer than 5 metres and weigh more than half a tonne.
The latest stranding happened near the road about 3km south of the Puponga carpark, and the whales would either be assessed during the night or this morning to determine whether they could be saved.
Beached whales often die from dehydration, collapsing under their own weight, or drowning when high tide covers the blowhole.
"It's disappointing and it's fairly intense for the guys on the ground. The first [DoC] staff have been on the ground for 12 hours so we've got back-up staff coming from Motueka."
There was also a possibility the rest of the pod could beach again overnight.
Pilot whales need a matriarch or female leader to guide them out to sea but it's not known if the pod's leader is injured or dead or if that's the reason for the strandings.
Yesterday afternoon 20 whales had to be euthanised after they restranded following a successful refloat of Friday's 100 beached whales.
Those whales were the survivors of a mass stranding of 416 whales on Thursday night at the sand spit.
Though yesterday's refloat on the high tide was successful, it's thought the 100 survivors - who met with another pod of 200 - did not make it the 26km out of the sand spit to safety before low tide at 5pm.
The plan last night was to water the mammals until dark and return as early as possible today to continue the rescue effort.
"They want all hands on deck tomorrow morning, early, as soon as people can get there."
Any volunteers must have a wetsuit.