The first settlers arrived in Australia at least 65,000 years ago, drastically altering the known history of the trek out of Africa by modern humans, a study has found.

The world-first finding, which follows years of archaeological digging in an ancient camp-site beneath a sandstone rock shelter within the Jabiluka mining lease in Kakadu, Northern Territory, also found that the settlers were sophisticated tool-makers of their time, reports the Press Trust of India.

Aboriginal people have lived in Australia for a minimum of 65,000 years, a team of archaeologists has established, 18,000 years longer than had been proved previously and at least 5,000 years longer than had been speculated by the most optimistic researchers, The Sydney Morning Herald reported.

The findings, which are already causing intense interest in archaeological circles across the world, have been peer reviewed by internationally recognised scientists and are published this week in the world’s most prestigious science journal, Nature.

Among the trove of discoveries are the world’s oldest stone axes with polished and sharpened edges, proving that the earliest Australians were among the most sophisticated tool- makers of their time: no other culture had such axes for another 20,000 years.

‘The axes were perfectly preserved, tucked up against the back wall of the shelter as we dug further and further,’ leader of the international team of archaeologists, associate professor Chris Clarkson of the University of Queensland told Fairfax Media.

‘There was one on the surface, another further down that we dated at 10,000 years. Then there were quite a few further down still which were able to date at 35,000 to 40,000 years, and finally one at 65,000 years, surrounded by a whole bunch of stone flakes,’ Clarkson said.

The team had also found the oldest known seed-grinding tools in Australia, a large buried midden of sea shells and animal bones, and evidence of finely made stone spear tips.

Professor Clarkson said one of the most striking finds was the huge quantity of ground ochre, right from the oldest layers. This suggested the first humans to populate Australia were already enthusiastic artists, and had continued to be so through their continuing culture in an area known for its spectacular rock art.

One major significance of the discovery is that archaeologists will have to recalibrate previous assumptions about the journey out of Africa by modern humans. Most academics believe the trek began between 80,000 and 100,000 years ago, but until now there was no solid evidence that humans had reached south-east Asia, let alone Australia, for anything beyond 50,000 years.