Japanese resources giant Inpex said on Monday it will explore commercial production of natural gas at a site off western Japan, marking the first attempt to develop a domestic gas field in about 20 years.

The site lies just over 100 kilometers off Yamaguchi and Shimane prefectures in the Sea of Japan. A government survey has located deposits of natural gas and oil 240 meters below sea level.

Inpex said it plans to carry out exploratory drilling over a period of about four months from March, to determine whether the area has enough gas to make commercial production feasible.

The company plans to split the operational cost of 33 billion yen, or about 290 million dollars, with JOGMEC, a government-affiliated resources corporation.

Japan now imports most of its liquefied natural gas for power plants, household supplies and other purposes.

The country's energy agency estimates that the targeted site could provide enough gas to cover 1.2 percent of Japan's annual domestic consumption.