A group of researchers led by Australian scientists were believed to have found the world's oldest rock on Canada's Hudson Bay Coast. The rock found was dated 900 million years earlier, the journal Geology reports.

The stone was identified at Nuvvuagittuq greenstone belt, 4.4 billion year-old and was possibly formed by impact of tectonic plates colliding with each other through a process identified as subduction.

The discovery was considered the boldest discovery to date as life may have started far earlier than what had been previously believed.

"Modern subduction settings, such as the Mariana arc, have all the right chemical ingredients to grow and sustain primitive life forms. From the similarities of our research into the earlier deposits from Canada, it follows that the conditions for the formation of life may have existed much earlier, with subduction starting far longer ago than we'd thought previously," Lead author, Macquarie University's Professor Simon Turner said.

"We expect that this research will result in a lot of debate across the discipline, as there's much that is yet to be discovered in the processes and earliest records of subduction. Our next steps are to investigate Zn isotopes which could show whether high pH fluids were present to stabilise amino acids, and we'll continue to explore the secrets under the Earth's crust."

However, the same scientists were in debate as subduction in Quebec where the stone was found was similar to stones found in subduction area near Japan which was found to be younger in years.

"Rocks that old get cooked and metamorphosed and deformed, (which) may destroy the evidence.(But) it's a matter of continuing to look. I don't believe this rock sequence has been closely investigated for any forms of life," Mr Turner explained.

Mr Turner, however, emphasised that the Australian discovery made a significant impact in the study of the origin of life.

"When I was an undergraduate, life started in the Cambrian (period), 500 million years ago. Here we are 20 years on, and there's ample evidence back as far as 3.5 billion years. Now, these studies suggest the conditions were appropriate as long as 4.4 billion years ago. It doesn't necessarily mean life did start then, but it opens the case that it could have."