Beijing will seek to build 50 new LNG tankers by 2020 as part of its quest to secure an energy supply chain, and to boost its ailing shipbuilding sector, Reuters reports.

According to the news service, six home-built tankers, constructed by Hudong-Zhonghua, accounted for half of the communist giant's LNG imports last year, the rest coming on chartered ships.

"China – under pressure to switch from coal to cleaner fuels to cut carbon emissions and clean its polluted air – plans to more than double its total gas supply by 2020, and is looking to triple its LNG imports to around 60 million tonnes, or about 82 billion cubic metres," Reuters said.

Estimates from ship safety agency the American Bureau of Shipping mean the 50 vessels will account for about a fifth of the 225 high-tech vessels to come online during the period – each set to cost about $US200 million – taking the global fleet to 394.