The ancestors of Aboriginal people in Australia arrived in several large and deliberate migrations by island-hopping to reach West Papua more than 50,000 years ago, according to research published in journals Scientific Reports, and Nature Ecology and Evolution.

"It took more than 1,000 people to form a viable population. But this was no accidental migration, as our work shows the first arrivals must have been planned," the Australian experts said in a statement on Tuesday.

"Our data suggests the ancestors of the Aboriginal, Torres Strait Islander, and Melanesian peoples first made it to Australia as part of an organised, technologically advanced migration to start a new life."

Human occupation on the Australia-New Guinea ancient mega-continent, known as Sahul, represented the earliest and indirect evidence for seafaring by humans anywhere in the world.

The multi-disciplinary researchers used sophisticated modelling to determine the likely routes travelled by the first people, as well as marine and navigation capabilities used to make the deliberate journeys, and the sizes of groups required for the population to survive in harsh conditions.

The study said the groups had sophisticated technology and knowledge of how to build watercraft as well as the remarkable ability at that time to plan, navigate, and make multiple complicated, open-ocean voyages to directly transport large numbers of people.

The researchers also used complex mathematical modelling, while considering factors like fertility, longevity, survival rate, climate conditions, and other ecological principles, to calculate the numbers of people required for the population as a whole to survive.

At least 1300 people might have arrived in either a single migration event or smaller, successive waves averaging at least 130 people every 70 years or so over the course of about 700 years, the study said.

"This suggests planned and well-organised maritime migration, rather than accidental arrival," said one of the authors, Corey Bradshaw, a professor at Flinders University.

US anthropologist Joseph Birdsell first suggested in 1977 two routes to Australia - one, via Timor to the north-west coast of Australia and a second, via West Papua.

But the Australian researchers have concluded the Aboriginal ancestors likely sailed from South-East Asia and island-hopped to West Papua New Guinea since it "would probably have been easiest to navigate and survive."

"This route was easiest when compared to the southern route from Timor that leads to the now-drowned Sahul Shelf in the modern-day Kimberley region," Prof Bradshaw said.

Australian Associated Press