A freak discovery, fate and a fascination with dinosaurs are behind a scientific breakthrough that has led to the identification of a new prehistoric species.

Key points: Weewarrasaurus pobeni was a two-legged, plant-eating dinosaur about the size of a kelpie dog

Weewarrasaurus pobeni was a two-legged, plant-eating dinosaur about the size of a kelpie dog The opalised jaw was found near Lightning Ridge and is approximately 100 million years old

The opalised jaw was found near Lightning Ridge and is approximately 100 million years old Weewarrasaurus is the first dinosaur to be given a scientific name in NSW in almost a century

Weewarrasauras pobeni is the first dinosaur to be named in New South Wales in almost a century, following a chance discovery of a jawbone fragment in a bucket of opal rubble near Lightning Ridge.

It was a two-legged, plant-eating dinosaur about the size of a kelpie dog that roamed the ancient floodplains in the state's north 100 million years ago.

The name honours the Wee Warra opal field, where the fossil was found, and opal buyer Mike Poben, who saw something special in the specimen and donated it for research.

"I was drawn to it straight away," Mr Poben said.

"It's like time stood still, I had prickles up the back of my spine because there was something in the back of my head saying 'tooth', and if it was tooth it was jawbone, and if it was jawbone, which I've never seen before, they're so rare, then it was something major."

Mr Poben came across the fossil five years ago and shared it with palaeontologist Dr Phil Bell from the University of New England in Armidale.

"I remember Mike showing me the specimen, and my jaw dropped," Dr Bell said.

"I had to try hard to contain my excitement, it was so beautiful."

Dr Bell and his team spent the past two years investigating and identifying the 100-million-year-old jaw.

"There are certain features about the teeth that are a dead ringer for a group of dinosaurs we call ornithopods, and these are all characteristically relatively small, dog-sized, bipedal animals that eat plants."

The Weewarrasauras pobeni is the first dinosaur to be named in NSW in almost a century. ( Supplied: University of New England )

Lightning Ridge is the only place in the world where dinosaur bones routinely turn to opal.

The University of New England is now looking into acquiring mines known to produce fossils.

"Unfortunately, the fossil remnants we see are almost always part of mining spoil... but on another hand, we would never get to see even those fragments if it wasn't for mining," Dr Bell said.

The Weewarrasaurus jaw is now part of the Australian Opal Centre collection, the world's most diverse public collection of opalised fossils.

Mr Poben's fascination with fossils remains strong and he continues to collect and inspect opal fragments.

He plans to donate his collection to the Opal Centre.

"I think they have to stay in Australia, and they need to be on display in Lightning Ridge. That's where they belong," he said.