China State Shipbuilding Corp (CSSC) has signed an agreement to build 18 ultra-large ships for QatarEnergy to transport liquefied natural gas (LNG), Chinese state broadcaster CCTV said on Monday.

The agreement was signed at a ceremony on Monday, CCTV said, adding that the vessels would be the world's largest with a capacity of 271,000 cubic meters each.

In March, QatarEnergy said it had finalised a number of charter contracts with several Asian ship owners to bolster its shipping fleet by 19 LNG vessels ahead of a massive expansion in LNG output.

An expansion of the North Field project by QatarEnergy, the world's top LNG exporter, includes eight LNG trains that will raise Qatar's liquefaction capacity from 77 million tons per annum (mtpa) to 142 mtpa by 2030, an 85% increase in production. (Reporting by Emily Chow in Singapore and Beijing newsroom; Editing by Kim Coghill and Subhranshu Sahu)