Vietnam National Shipping Lines (Vinalines) said it will invest about $2.4bn to increase its fleet tonnage from six million dwt to seven million dwt.
The ships, to be built in Vietnamese yards, will be delivered between 2010 and 2015, the company said.
Vinalines deputy general director Nguyen Hung Viet said the company would increase the capacity of its fleet by 350,000t to more than three million tonnes in 2010.
The expansion follows an increase of 320,000t of capacity in 2009, which saw the company's fleet reach 2.7 million tons, Viet said.
Vinalines, which has 150 vessels of 2.7 million dwt, is also planning to acquire second-hand tonnage including VLCCs, Aframaxes and product carriers.