Nicknamed Banjo he had three large slashing claws on each hand and is the most complete meat-eater ever found in Australia.

His remains were discovered near those of two other dinosaurs - new species of giant plant eaters - at Winton, in western Queensland.

Dubbed Clancy and Matilda, they lived about 100 million years ago and were titanosaurs, the largest kind of dinosaurs ever to have lived.

Queensland Museum Palaeontologist, Scott Hucknell, said the carnivore, Australovenator wintonensis, was even bigger and more terrifying than velociraptor.

"The cheetah of his time, Banjo was light and agile. He could run down most prey with ease over open ground."

The dinosaurs have been named after Banjo Patterson and the characters in his poetry, because he composed Waltzing Matilda in Winton in 1885, and it was first performed there.

Clancy, Witonotitan wattsi, was a tall slender animal, while Matilda, Diamantinasaurus matildae, was more stocky and hippo-like.

Banjo and Matilda - possibly predator and his prey - were found buried together in a 98 million year old billabong.

The find is published in the journal Public Library of Science One, and was announced by Queensland Premier, Anna Bligh, at the Australian Age of Dinosaurs Museum of Natural History in Winton.

"These discoveries are a major breakthrough in the scientific understanding of prehistoric life in Australia," Ms Bligh said.

Museum Victoria palaeontologist, John Long, said the finds were "amazing" and put Australia back on the international map of big dinosaur discoveries for the first time since 1981, when the discovery of Muttaburrasaurus, a large four-legged herbivore that could rear up on two legs, was announced.