South Korea's Navy will receive a new diesel-electric air-independent propulsion submarine Friday capable of staying underwater more than 10 days, the state arms agency said.

The Defense Acquisition Program Administration plans to deliver the Hong Beom Do submarine to the Navy in a ceremony at the shipyard of Hyundai Heavy Industries in Ulsan.

Named after a respected independent fighter during Japan's colonial rule in the early 1900s, it's the seventh of South Korea's 214-type Son Won Il-class subs.

The Navy will put it in combat operations in May after training a crew.

The Son Won Il-class sub is a sharp improvement in major capabilities, including underwater operations, stealthiness, sonar ability and armament, compared with the 1,200-ton Chang Bo Go-class one.

It's the world's top-level diesel sub that can handle more than 300 underwater targets at the same time and operate underwater for over 10 days without surfacing, the DAPA said.

The 1,800-ton sub is 65 meters long and 6.3 meters wide.

"On the basis of superb underwater operation capabilities, it will add to our Navy's underwater firepower, which is inferior to North Korea in number," said Choi Hee-kyung, head of the agency's submarine program team.

South Korea has less than 20 submarines, while the North reportedly possesses 60-70 submarines. (Yonhap)