Whale rescuers remain on high alert at Farewell Spit as they warn a group of pilot whales, refloated for a second time today, could still get confused and head back to shore.
The whales were part of a pod of 99 that beached in the Farewell Spit area in Golden Bay around midday on Monday.
A group of whales refloated yesterday but, after about three hours of "milling" about in shallow water, 40 restranded yesterday afternoon.
Five died and another two had to be euthanised this morning, Department of Conservation (DoC) area manager John Mason said.
The remaining 33 stranded whales were successfully refloated at high tide today, at about 11.40am, but they appeared happy to stay in the general area.
But about 1.30pm, the pod appeared to change tack and slowly started heading offshore in a south-easterly direction towards the deeper sea, Mr Mason said.
"They aren't moving quickly, but they do seem to be reasonably consistent in the way they're heading. We've got a boat shadowing them, and we'll have a boat shadowing them for the rest of the night for as long as we can.
"They're obviously not in perfect condition, they've been on the beach for the last 48 hours, but I guess they've got enough energy to swim and they seem to have a bit of motivation today too, which they didn't seem to have yesterday."
Kimberly Muncaster, chief executive of whale rescue group Project Jonah, said the whales were making great progress tonight.
"They are swimming really well together. We left them in quite a good position, they have moved about 4km offshore basically. They were in deep water and swimming freely."
But the whales were not in the clear yet.
"There's sadly every chance they of course could just turn around and come back in the wrong direction because the spit is incredibly confusing for them and there's lots of sand bars all over the place.
"But we've passed that low tide mark and they're still in the water, so at this point we're really hopeful."
Conditions around the spit were constantly changing, but the whales were in at least two metres to 3m of water.
Project Jonah volunteers would remain in the area tomorrow.
"We're still on high alert and we'll certainly be mobilising our volunteers tomorrow if help is needed."
Up to 200 DoC and Project Jonah workers and volunteers have helped to keep the whales comfortable, wet and shaded during the last two days.
Ms Muncaster thanked the 50-odd Project Jonah volunteers who came to the rescue on Monday, and the extra workers who arrived today to support the tired volunteers.
"These people have done an extraordinary job. Along with DoC staff and members of the public, they've endured challenging conditions on the beach, little sleep, and heartbreak when the whales restranded."
Ms Muncaster said the volunteers' commitment to starting all over again, despite being tired, was "truly admirable".
DoC's Mr Mason said the carcasses of the dead whales have been moved to behind a sand dune where they would decompose out of the public's way.
A smaller group of 17 whales which refloated themselves on Monday night appeared to be safely back at sea.
Another 36 whales have died since the original stranding, and six are unaccounted for.