BG Group has approved an investment of £9.3 billion ($US15 billion) for a liquefied natural gas project in north east Australia.
The project will involve building a 540km pipeline from where coal seam gas will be extracted, to a plant where it will be processed into liquefied natural gas.
BG said on Sunday that the investment was a "milestone" in its expansion.
Environmental approvals were issued by the Australian government last month.
The BBC reports the Queensland Curtis liquefied natural gas project will be the first plant in the world to convert coal seam gas into LNG.
The intention is to produce 8.5 million tonnes of LNG annually - the equivalent to about 10% of all of the gas used in Britain each year.
The LNG will mainly be sold in Asia, with the first exports planned for 2014.
BG already has customers in China, Japan, Singapore and Chile lined up.