"They signed a letter of intent at this stage," the source familiar with the matter said, declining to be identified because he was not authorised to speak to the media.
A nuclear crisis in Japan following last month's massive earthquake could boost a nascent recovery in LNG ship orders, a senior executive at Daewoo Shipbuilding & Marine Engineering said last week.
A Samsung spokesman said the world's third-largest shipbuilder was still in negotiations with the shipper and the result might come out as early as next week.