The source also said that the Russian gas export monopoly may double the plant’s annual capacity to 20 million tons if talks with the Korean company, the world’s largest corporate buyer of LNG, are successful.

“KOGAS is actively interested in purchasing LNG from Vladivostok. We have discussed the matter with our Japanese partners,” the source said.

A Gazprom spokesperson declined to comment.

The project to build the plant in Russia’s Pacific port of Vladivostok is being discussed with a consortium led by Japanese trading house Itochu Corp. and Gazprom, who may invest some $7 billion.

Earlier this week, South Korea announced long-term agreements worth $84 billion with energy giants Royal Dutch Shell and Total to buy gas from LNG projects in Australia.

South Korea, the world’s second-largest buyer of LNG after Japan, needs the deals to replace supply from Indonesia, Malaysia and Brunei under agreements due to expire between 2013 and 2015.

Gazprom also plans to build a gas pipeline to South Korea, but the project has been complicated by the fact that the shortest way to lay the link is through the territory of Seoul’s old foe, North Korea.

The Russian company has been losing its market share in Europe — its main source of revenue — where it satisfies some 25 percent of gas needs, on the back of a slower demand and shifting focus to unconventional gas consumption.

Gazprom already operates an LNG plant on the Pacific island of Sakhalin, where it produces 10 million tons of the frozen gas every year.

It also signed memorandums of understanding to supply Indian companies with a total of 10 million tons of LNG a year as it plans to implement another LNG project in the Barents Sea.