Tests by the Australian Museum in Sydney will determine if the six-metre whale washed ashore at The Pass, Byron Bay on Tuesday morning is a rare Longman's beaked whale.
All indications are that it is, according to National Parks and Wildlife Service spokesman, Lawrence Orel, which will make it only the second of its kind to be found beached in Australia.
Mr Orel said the only other stranding of a Longman's beaked whale in Australia was recorded in North Queensland more than 100 years ago.
He said the whale was alive when first spotted off Fisherman's Lookout, but was dead by the time it was beached.
An initial autopsy found nothing out of the ordinary other than it was an old female, he said.
Said Mr Orel: "It's definitely a beaked whale and it's likely to be a Longman's whale, but given the paucity of information about them, the skull will confirm what it is."
Beaked whales normally live in deeper water and are rarely seen.
Update your news preferences and get the latest news delivered to your inbox.