SINGAPORE, Dec 10 (Reuters) - South Korea is more than doubling the Ulsan port's oil storage capacity by 2020 to meet the country's rising oil demand, a senior port official said on Tuesday. Throughput at the port has increased 3 percent annually from 2001 due to firm oil demand in the world's fifth-largest crude importer, said Chong Rok Park, president of Ulsan Port Authority, at a storage conference in Singapore. Volumes could grow further with the country signing several free trade agreements to boost trade flows, and the use of new shipping routes including via the Arctic, which may increase the need for oil storage, he said. To meet this demand, construction of a new terminal with a total capacity of 28.4 million barrels has begun recently. That will more than double the current capacity of 21 million barrels in 10 commercial tanks, said Park. It will be built in two phases, with the first known as the North Port having a capacity of 9.9 million barrels on 295,000 square metres area, which will mostly store oil products. The first phase is expected to be completed by 2016 and will be ready for operations by 2017. Companies involved in the development will include Korea National Oil Corp (KNOC) and Vopak, Park said, declining to reveal names of other companies who have indicated an interest. The second phase, or the South Port, will focus on crude oil and is expected to have a capacity of 18.5 million barrels on 604,000 square metres area. The port authority is also planning to build a pipeline to connect the terminal to refineries such as SK Energy and S-Oil Corp, which have a total refining capacity of nearly 1.5 million barrels-per-day, and to other storage facilities, said Park. (Reporting by Jessica Jaganathan; Editing by Muralikumar Anantharaman)