A false killer whale that had stranded north of New Brighton in Christchurch has now disappeared from sight - giving rescuers high hopes it will survive and rejoin its pod.
The whale was one of two that were found stranded first thing this morning, although the other was dead.
Project Jonah general manager Daren Grover said medics started re-floating the whale an hour ahead of the high tide.
Mr Grover said the operation went smoothly, and that the local false killer whale population is only about 120, so they're really hopeful it will survive.
Earlier, volunteers worked with the Department of Conservation to save the stranded whale.
Two whales were reported stranded on Waimairi Beach at first light this morning but one had died.
Project Jonah, a volunteer organisation which works to protect whales and dolphins, had been on alert for strandings since a pod of pilot whales was spotted off the shore of Banks Peninsula yesterday afternoon.
Six years ago there had been a mass stranding at Port Levy, said Project Jonah manager Daren Grover.
"Memories of that are still there so we thought 'let's put our medics on standby'."
About 15 trained volunteers were working with DoC and Canterbury Regional Council staff to keep the whale cool and calm with the intention to float it back out to sea when the tide came in at 4 o'clock this afternoon.
The whale was not obviously unwell but there was the possibility it had stranded itself because it was sick, Mr Grover said.
A health check for the whale was carried out soon.
"The initial prognosis is good but until we know more we can't make a decision. There are several plans of action we could take, one of which is putting the whale down if it is sick."
Mr Grover asked people coming to take a look at Waimairi Beach to follow the volunteers' instructions and keep dogs and small children away from the whale for their own safety.