Fossils of three new species of dinosaurs have been discovered in Australia suggesting it may have a more complex prehistoric past.

The two plant-eating and one carnivore dinosaurs, the first large dinosaurs unearthed since 1981, were found in Queensland and date back 98m years to the mid-Cretaceous period.

‘It not only presents us with two new amazing long-necked giants of the ancient Australian continent, but also announces our first really big predator,’ palaeontologist John Long, head of sciences at Museum Victoria said on Friday.

Palaeontologist Ben Kear at La Trobe University in Melbourne said the discovery will pave the way for new studies on Australian dinosaurs and their environments.

‘Australia is one of the great untapped resources in our current understanding of life from the Age of Dinosaurs,’ Mr Kear said.

‘The discoveries...will definitely reinvigorate interest in the hitherto tantalizingly incomplete, but globally significant record from this continent...’

The new dinosaurs were unearthed during joint Australian Age of Dinosaurs Museum and Queensland Museum digs at Winton in outback Queensland.

The meat-eating theropod dinosaur has been called Australovenator (nicknamed Banjo after Australian bush poet Banjo Patterson) and the two plant-eating sauropod dinosaurs are Wintonotitan and Diamantinasaurus

‘Banjo’ sheds light on the ancestry of the largest-ever meat-eating dinosaurs, the carcharodontosaurs, a group of dinosaurs that became gigantic, like Giganotosaurus, he said.

The two herbivore dinosaurs were different kinds of titanosaur, the largest type of dinosaur ever to have lived.

Wintonotitan was a tall animal which may have fitted into a giraffe-like niche, while the stocky Diamantinasaurus was more hippo-like, said Hocknull.

Two of the dinosaurs were found buried together in a 98m-year-old waterhole.