Trading house Sumitomo Corp said on Monday it had won a $300 million order for a 400-megawatt gas-fired power plant in Turkmenistan, part of a package of deals announced on a visit to the Central Asian nation by Japanese Prime Minister Shinzo Abe.

Japan and Turkmenistan on Friday signed deals worth over $18 billion in the energy-rich nation, which has become an important supplier of natural gas to China.

Turkmenistan, a reclusive nation of 5.5 million, holds the world's fourth-largest reserves of natural gas. Since independence in 1991, it has launched ambitious projects to process the commodity at home and find new export routes.

Japan's Abe last week started a tour of the five post-Soviet Central Asian nations where former imperial master Russia and China are vying for clout.

Japanese companies are already involved in large-scale projects in Turkmenistan, building plants to process natural gas into fertilisers, ethylene, polyethylene and polypropylene, as well as into liquid fuel.