TOKYO (Reuters) - Osaka Gas Co, Japan's second biggest supplier of city gas, has identified offshore Mozambique as one of several regions in which it would be interested in making an upstream investment, a senior company official said on Thursday.The Osaka-based company is also looking at cooperating with Tokyo Gas in buying liquefied natural gas (LNG) from one of the many projects planned from resources offshore the east African nation, the official said."We are looking not only at Mozambique but also others as well," Takayuki Tasaka, the company's associate director and general manager of corporate strategy department, told Reuters.Recent discoveries have boosted Mozambique's gas reserves to around 150 trillion cubic feet (tcf), enough to supply Japan for 35 years. The east African country is expected to eventually compete with Australia and Qatar as a major LNG source for Asia.LNG buyers often take stakes in upstream gas projects in deals that also guarantee a contractual offtake of the fuel.Japan's Mitsui & Co, which has a 20 percent stake in the Anadarko Petroleum-led Area 1 prospect, has said it aimed to sell at least 5 million tonnes per annum (mtpa) of Mozambique LNG to Japan, the world's biggest importer.Anadarko and India's Videocon Industries last month launched a sale of a 20 percent stake in Area 1 that may fetch $4.5 billion. Anadarko holds a 36.5 percent of the block, while India's Bharat Petroleum Corp Ltd and a unit of Videocon Industries hold 10 percent each.Italian oil firm Eni, which operates the neighbouring Area 4 prospect in Mozambique, and Anadarko have said they plan to unite exploitation of the two offshore fields to boost their value.The two planned 5 mtpa LNG production plants, known as "trains", are expected to start operations as early as 2018, Anadarko has said.Osaka Gas now imports about 8 million metric tonnes of LNG a year. By 2020, its annual purchases of LNG will have grown to around 10 million tonnes a year, of which about 20 percent will be linked to gas benchmarks instead of oil, Tasaka said.Japan's total LNG imports rose to a record 87.3 million tonnes last year as utilities ramped up oil and gas-fired power generation to make up for the near halt in the use of nuclear power after the 2011 radiation crisis at the Fukushima Daiichi nuclear plant northeast of Tokyo.