Beached whale on NSW coast euthanised

A juvenile humpback whale that has been beached on the NSW mid north coast for more than a day has been euthanised after its condition worsened.

"It's been a very, very difficult afternoon for everybody involved," marine rescue organisation Orcca vice president Shona Lorigan told AAP on Saturday from Sawtell Beach, south of Coffs Harbour.

Ms Lorigan confirmed the young whale, weighing about 10 tonnes, was put down about 1pm.

It was first spotted by beachgoers early on Friday but rough sea conditions hindered rescue attempts.

"Mother nature's not helped us today, the waves are getting bigger as I watch," Ms Lorigan said.

"We had no hope of getting boats in until at least Monday."

She said experts had been monitoring the whale overnight and saw its health deteriorating.

"We really had to think of the welfare of the whale and we didn't want it to suffer any longer," she said.

The yearling whale was likely making its first migration from Antarctica to Queensland after being weaned, she said.

"It's quite a long and arduous journey," she said.

"If an animal is in poor health or if it's weaker then the time it will get into trouble is when it's making that huge journey."

Arrangements are being made for the whale to be taken off the beach and buried.