The plane crashed shortly after taking off from an airport in Indonesia.
188 people were on board Lion Air flight JT-610 when it disappeared from radar and crashed into the sea north of Jakarta.
It took off from Jakarta at 06:20 local time on Monday morning and was due to arrive at Depati Amir airport in Pangkal Pinang an hour later but about 13 minutes into the flight, authorities lost contact with the plane.
The pilot had asked to return to Jakarta's Soekarno-Hatta airport, the head of Pangkal Pinang's search and rescue office, Danang Priandoko, told local news outlet Kompas.
Indonesia’s search and rescue agency has confirmed the plane crashed.
'It has been confirmed that it has crashed,' Yusuf Latif, a spokesman for the agency said.
'We cannot give any comment at this moment, said Edward Sirait, chief executive of Lion Air Group.
'We are trying to collect all the information and data.'
A spokesman for DFAT said the Department of Foreign Affairs and Trade was aware of the reports.
'The Australian Embassy in Jakarta is making urgent enquiries with local authorities to determine if any Australians were affected,’ they said.