More animals have again stranded themselves on an island off Tasmania's north-west coast, a day after about 80 whales and dolphins beached themselves there.

Yesterday 60 pilot whales and 20 bottlenose dolphins were found on New Years Island, just a day after 13 other dolphins beached in Quarantine Bay on nearby King Island.

Of the mammals beached on New Years Island, crews saved six dolphins and just two whales.

Eight of the dolphins that beached on King Island were able to be saved.

Wildlife biologist Rachel Alderman says one of the rescued dolphins has re-beached and died and crews are now focussed on trying to save a whale which has stranded again.

"We've got the animal cool and wet, we're getting more people out there to try and move it into the water and just see how the animal is and it will dictate our next move," she said.

"We've had a pretty rewarding success given the circumstances. It's not at all uncommon for some individuals to come back and re-strand after going through such a traumatic, physically traumatic and I guess psychologically traumatic ordeal.

"We do the best that we can for them and hope that they can make it through."

Saturday's stranding is one of the largest in Tasmanian waters since 2009, when about 200 whales and dolphins beached on King Island.

Five dolphins died after beaching themselves on King Island on Friday. ( Supplied: Margaret Barnes )

King Island ranger-in-charge Shelly Davison says the mammals may have spent two nights on the beach before rescuers got to them.

"Most of the animals unfortunately were deceased," she said.

"We believed that they may have been there for two nights - given the remote location you don't always get these things reported."

Ms Davison says it has been a challenging experience for rescue crews.

"It is emotional but we've still got a job to do," she said.

"We're still focused on what we're doing and doing our job at the moment."

Ms Davison is hoping samples they take from the dead mammals will shed some light on what went wrong.

"It's not that common to get that stranding of both pilot whales and bottlenose dolphins but it did happen at the last stranding on King Island which is quite interesting," she said.

"We'll be collecting samples and doing a few autopsies on the deceased ones .

"We'll put all that information together so one day we might be able to work out why they do it."