Indian people may have arrived on Australian shores about 4000 years before Europeans colonised the continent, scientists report.

Modern humans are thought to have arrived down under about 40,000 years ago, having made their way out of Africa around the coast of the Arabian Peninsula and India to Australia.

Most scientists believed these ancestors of modern Aborigines remained isolated from other populations until Europeans appeared in the late 18th century.

But a genetic analysis of more than 300 Aborigines, Indians and people from Papua New Guinea and islands of south-east Asia has found a "significant gene flow" from India to Australia about 4230 years, or 141 generations, ago.

The study's lead researcher, Irina Pugach, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, said the arrival of these people during the Holocene coincided with many changes in Australia's archaeological record.