Fossilised teeth from the largest shark to roam the oceans are on sale in the French Pacific island of New Caledonia.

The teeth come from the Megalodon, an ancestor of the Great White Shark, which has been extinct for about one million years.

Each animal had at least 160 razor-sharp teeth, each up to 15 centimetres long.

The Megalodon constantly shed its teeth, hence the large numbers found in the Pacific.

A former wholesale butcher and marine enthusiast Alain Conan said he had recovered thousands of fossilised teeth while dredging the ocean.

"Along with some friends, I decided to set up a small company to sell the teeth," Conan said.

"We sell a dozen or so teeth a month. We sell direct to customers, to a few shops in Noumea and on the Internet."

But he said not all of them are suitable for selling.

"Of each 100 teeth, only around 20 or so can be sold. The rest are either broken or too damaged," he explained, adding that his company had several thousand in stock.

The teeth are polished or carved and then sold in a wooden presentation box, mounted as jewellery or used to decorate picture frames or lamp stands.

The fossilised teeth have become something of a trademark for the island and are often given by local officials to visiting dignitaries.

Teeth that still have enamel, roots or that are very small tend to attract more interest. Prices range from US$105 to US$735 each.

The deposits of teeth, lying in seas from 350 to 500 metres deep, were first discovered in 1985 by scientists surveying the ocean bed off the southeast of the island.

The vast Megalodon evolved around 25 million years ago and was found in oceans around the world. It was discovered and named by Swiss naturalist Louis Rodolphe Agassiz in 1835.

Its 15-metre length and 20 tonnes make it dwarf its descendant, the Great White, the largest recorded example of which measured just over seven metres.

Its extinction around one million years ago has been put down to dwindling food stocks and climatic change.

According to some scientists, Megalodons lived in deep caves particularly off Java and Indonesia, but the theory still has to be proved.