A rare set of teeth from a prehistoric shark that was more than twice the size of the ferocious great white shark has been unearthed on Victoria's coastline.
The chance discovery of more than 40 teeth from a Carcharocles angustidens shark that lived 25 million years ago has excited palaeontologists because it's the first time a set of the seven centimetre-long serrated chompers have been found in Australia.
While many individual teeth from this species of mega-toothed shark and its ancient relatives have been found around the world, only two other sets have previously been unearthed in New Zealand and Belgium.
Amateur fossil finder and school teacher Philip Mullaly initially discovered about eight teeth sticking out of a boulder at Jan Juc, near Torquay, about two years ago and contacted Museums Victoria.
Dr Erich Fitzgerald, the museum's senior curator of vertebrate palaeontology, organised his team to undertake a dig at the site in last year and uncovered more than 40 teeth and part of the shark's backbone.
"They are as sharp as they were the day they were being used to slice through the flesh of whales," he told AAP.
"Think a steak knife. They're sharp."
Carcharocles angustidens grew to more than nine metres and feasted on small whales and penguins while swimming the world's oceans between 33 and 22 million years ago.
The species was an ancient cousin of the infamous Megalodon, which at three times the size of the great white was the biggest and most ferocious shark to have ever lived before dying out about 2.6 million years ago.
Mr Mullaly, a school teacher from Geelong, was "blown away" when he found the first few teeth in pristine condition.
"I was in a bit of shock actually because I saw it and I thought this is looking like it's complete, like it's just fallen out of a shark's mouth even though it's 25 million years old," he said.
Suspecting they were a rare find, Mr Mullaly contacted Dr Fitzgerald, who he knew from previous discoveries of whale fossils.
Dr Fitzgerald said teeth and bits of vertebrae are usually the only parts of a shark's body that are found by fossil hunters as the creature is made up mostly of cartilage, a soft tissue that doesn't fossilise well.
"So to have fossil finds like this one from Jan Juc where there are several teeth and part of a vertebra is pretty rare," he said.
The collection of teeth will go on public display for six months at Museums Victoria, Melbourne.
"People can get a real sense of the past from seeing them," Mr Mullaly said.
"They're really beautiful objects."