Wildlife authorities are euthanasing what remains of a false killer whale pod that stranded itself on Tasmania's west coast, as they consider the steps that follow.

Department liaison officer Brendon Clark said the stranding was the first by false killer whales in Tasmania in since 1974. That was a pod of more than 160 whales that landed on a beach near Stanley on the northwest coast. Strandings in Tasmania are usually pilot whales.

The animals appear to be false killer whales, according to Tasmania’s Department of Natural Resources and Environment.

The animals are part of a pod of 157 whales that beached near Arthur River, a township in Tasmania. What caused them to beach remains unclear.

Unfavourable ocean and weather conditions thwarting rescue efforts are forecast to persist for days and the surviving animals will be euthanised.