The isolated Central Asian country holds the world's fourth-largest natural gas reserves and has in recent years sought to diversify an economy battered by low energy prices.

The plant opened in the desert town of Ovadan-Depe outside the capital Ashgabat with Japanese and Turkish investment is the largest gas-to-liquids plant in Central Asia.

“Our country keeps pace with scientific progress,” Turkmen President Gurbanguly Berdymukhamedov said at the opening ceremony.

“We want Turkmenistan to become the centre of a ‘green’ economy.”

In a message read out at the ceremony, Japanese Prime Minister Shinzo Abe said he was glad that Japan helped diversify Turkmenistan's economy and ramp up energy exports.

The plant will process 1.785 billion cubic meters of natural gas annually, producing 600,000 tons of gasoline a year among other liquid fuels.

The plant was built by Turkey's Rönesans and Japan's Kawasaki Heavy Industries. Construction began in 2014.

Japanese companies have recently ramped up investments in Turkmenistan, a country overwhelmingly dependent on gas exports to China via the Central Asia-China gas pipeline completed in 2009.

In building a gas plant to convert gas into liquid fuels, Turkmenistan emulated Qatar.

Other mega-pipeline projects involving Turkmenistan including one to India and another to Europe via the Caspian Sea have long been held up by questions of economic and political feasibility. 

The secretive country of 5.7 million people suffers from widespread unemployment and economic stagnation.

At the beginning of the year the government hiked fees for utilities, including water, gas and electricity which were once free.

Turkmenistan's neighbor Uzbekistan is reportedly planning a similar plant that will produce around 1.5 million tons of liquid fuels per year.