China is the world's largest buyer of the super-chilled gas, while CNOOC is the country's largest importer of the fuel and among the state majors leading a drive to expand their LNG fleet to meet rising import needs and facilitate fast-growing global trade.

The 12 vessels will be built by Hudong Zhonghua Shipbuilding Co, a unit of China State Shipbuilding Corporation (CSSC), utilizing the so-called fifth-generation LNG tanker technology that reduces fuel consumption and carbon emissions, CNOOC said in a statement on its website.

Each tanker can carry up to 174,000 cubic meters of LNG, equivalent to 108 million cubic meters when re-gasified.

The vessels are slated for commissioning between 2024 and 2027, CNOOC said.

The company, which first imported LNG in 2006, has built 10 LNG tankers and also engaged in joint vessel designing in tie-ups with CSSC.

CNOOC is the parent of Hong Kong and Shanghai-listed CNOOC Ltd and overseas the group's business such as oil refining and natural gas trading, excluding offshore oil and gas production.

($1 = 6.6080 Chinese yuan renminbi)

(Reporting by Chen Aizhu; Editing by Vinay Dwivedi)