As Japan's long-term contracts to secure liquefied natural gas (LNG) from Russia's Sakhalin-2 project near expiration, rival producers see opportunity to fill the supply gap, even as Tokyo looks to switch to cleaner energy, industry insiders say.

The country's declining demand for gas plus geopolitical pressure on Tokyo to curb its reliance on fuels from Russia mean Japanese buyers may not want to renew all of their contracts with a supplier long favored for its proximity and reliability.

Japan, the world's second-biggest LNG buyer, depends on Russia for 9% of its LNG, or 6 million metric tons per year, 5 million of which come from the long-term contracts at Sakhalin-2 run by the Kremlin-controlled Gazprom.