Woodside Petroleum's huge Aus$14.9 billion (US$15.5 billion) Pluto project began its liquefied natural gas (LNG) output on Monday ready to be shipped to Japan, seven years after the initial discovery.
The Australian energy producer, whose project has been dogged by delays and cost blow-outs, called production a defining moment in its history.
"Pluto cements Woodside's position as a major supplier of LNG to the Asia-Pacific region and builds on our position as a global leader in upstream oil and gas," said chief executive Peter Coleman.
Pluto is among around a dozen gas-export terminals planned in Australia, potentially catapulting the country ahead of Qatar as the world's largest exporter of LNG by the end of the decade.
But its development was delayed several times by construction workers going on strike, labour shortages and the reinstallation of flare towers that were not cyclone-proof.
Pluto, whose joint venture partners are Japan's Tokyo Gas Pluto and Kansai Electric Power, is forecast to produce 4.3 million tonnes a year.
Resources Minister Martin Ferguson said it was a "momentous" announcement for Woodside and Australia.
"This project is very important to the energy industry and the national economy more broadly," he said, adding that 15,000 jobs were created during construction, pumping some Aus$7.6 billion into the economy.