A rare beaked whale washed up in Australia Tuesday, exciting researchers who know little about an animal that spends much of its time diving at depth far from shore.

The three-to-four metre (10-13 feet) long whale was found dead at Redhead Beach, some 150 kilometres (93 miles) north of Sydney, with experts examining it and taking specimens before sending its head to the Australian Museum in Sydney.

"It is sad but also exciting as we can learn so much more about the animal," Organisation for the Rescue and Research of Cetaceans in Australia president Ronny Ling told AFP.

"We don't know much about them, we rarely get to see them. We have taken samples and measurements and will remove the head and send it to the Australian Museum.

"The jaws will be X-rayed and together with DNA it should confirm the species of beaked whale."

According to the whaleresearch.org website, the study and knowledge of the beaked whale family, one of the deepest diving of all cetaceans, is limited because they favour such deepwater habitats.

"What little we know of beaked whales has largely come from stranded animals," it said.

"Sightings of these elusive creatures at sea are extremely rare due to their long dive times and unobtrusive surfacing behaviour."

A study published this year in the journal PLOS ONE showed one tagged Cuvier's beaked whale dived to 2,992 metres (9,816 feet), while another stayed underwater for 137.5 minutes.

These were both new mammalian dive records.

Ling said that in 25 years he had come across few beaked whales.

"Some of these species are only known from a handful of strandings," he said.

Marine biologist Elise Bailey told ABC radio she had never seen a beaked whale in her 20 years of study until now.

"You don't normally see a beaked whale come into these waters; it's an oceanic animal and it's usually going to be way out in very deep offshore waters," she said, adding that it was too early to say why the whale died.

"It could be sick, it could be old, it could have had some trauma," she said.