A discovery of well-preserved fossils in Western Australia's Pilbara region has revealed that life on Earth existed earlier than thought - 270 million years ago.

David Flannery at the University of New South Wales Australian Centre for Astrobiology said that the find indicates the earliest sign of oxygenic photosynthesis yet found.

According to ABC Science, the fossils, which include stromatolites, microbially induced sediment structures and biomarkers, the molecules created when oxygen is made, were well preserved.

The fossil showed the presence of cyanobacteria, commonly known as blue-green algae, which are single-cell life forms that can photosynthesise oxygen, said Flannery.

The earliest published evidence for these organisms to date had been 2.45 billion years ago.

The find would help scientists solve the mystery of the oxygenation of the atmosphere will help exoplanet hunters to better target which planets may support life.

"If for example, we find it takes a billion years for the atmosphere to oxygenate, then we know it is not worth looking at stars less than a billion years old," he said. (ANI)