Four tattooing tools, including two believed to be made of human bones, were found on Tongatapu Island, the main island of Tonga, in 1963, but researchers have only recently been able to ascertain their significance.

The Polynesian style of tattooing is still practiced today with similar tools, showing how long the practice has continued.

"It’s an unbroken tradition and even people from the Cook exploration days went to Tonga in the 1770s and they noticed the Polynesian people were using tools that were very similar small bone combs used in the same way, so it's a very durable tradition," said Associate Professor Geoff Clark, from the Australian National University's School of Culture, History and Language.

While it may unsettle some to think that human bones had been fashioned into tools, Associate Professor Clark said it most likely added an extra layer of meaning to the tattoos, which are full of cultural significance.

"Because tattoos are making a permanent design on the body, for important life events or to show status or for medicinal use or protection, the fact that people are using tools to make this significant decoration and they are probably made from the bones of their ancestors shows the cultural importance of the tools," he said.

Researchers believe the artefacts - which include a narrow comb, a haft, a mallet, carbon pigment and a mortar and pestle - most likely belonged to one tattoo artist. An ink pot was also part of the original discovery, but is believed to have been lost in Canberra's 2003 bushfires.

"The question has always been: were these tools introduced to the Pacific through migration, or were they developed in Polynesia where we know tattooing has a very prominent role in society and spread from there?" Associate Professor Clark said.

"This discovery pushes ... the date of Polynesian tattooing right back to the beginnings of Polynesian cultures around 2700 years ago."

So how does the practice compare to the Western-style sterilised needles most people would be familiar with?

"I would say the hammering of the bone points into your skin is a lot more painful," said Associate Professor Clark, who has been tattooed using both the traditional method and the modern method.

"It's a very strange experience - they just hammer into your body and you just sit there very quietly."