With the approval by South Korea's Cabinet on Tuesday of the accord on sharing military intelligence, Seoul completed its domestic procedures to forge the accord and Tokyo is expected to complete its own procedures this week, the senior official at Seoul's foreign ministry said.
"As soon as Japan's Cabinet endorses the General Security of Military Information Agreement (GSOMIA), possibly within this week, we will formally sign the agreement with Japan," the official said on the condition of anonymity.
Since early 2011, Seoul and Tokyo have been in talks to forge two military pacts on military intelligence and logistics.
South Korean Defense Minister Kim Kwan-jin had planned to visit Japan last month to sign one of the pacts, the GSOMIA, but shelved the plan due to some territorial and other unresolved issues that have arisen from their shared past. Japan ruled the Korean Peninsula as a colony from 1910-45.
Military cooperation is one sensitive area that needs to be addressed in Seoul-Tokyo relations, but the two nations have lately agreed on the need to expand cooperation in the defense sector in the face of increasing military threats from North Korea, especially after the death of North Korean leader Kim Jong-il.
South Korea "needs the pact on sharing military intelligence with Japan because we have to use Japan's intelligence assets, including its spy satellites and high-end surveillance aircrafts," the ministry official said.
"It is an undeniable fact that the existence of Japan is important for our national security," he said, citing the presence of U.S. forces in Japan.
"In case of contingency on the Korean Peninsula, the U.S. Forces Japan will become a rear base for the U.S. Forces Korea," the official said.
About 28,500 U.S. troops, mostly ground soldiers, are stationed in South Korea and more than 35,000 U.S. troops, mainly consisting of navy, air force and marines, are stationed in Japan.
The official said the military pact with Japan is also taking aim at the rise of China.
"To cope with the rise of China, the military intelligence pact with Japan is needed to boost our intelligence capability," the official said.
The Seoul government had kept the approval of the pact with Tokyo secret, but made it public on Wednesday following a report by a local newspaper.
Asked why the government kept it secret, the ministry official replied, "Because the Japanese side has not completed its domestic procedures to sign the pact."
Critics denounced the government's move for military cooperation with Japan at a time when Tokyo has not fully repented for its wartime atrocities, including the issue of Korean women who were forced into sexual slavery by the Japanese military during World War II.
Rep. Kim Eul-dong of the ruling Saenuri Party told Yonhap News Agency, "Various issues remain unresolved between Korea and Japan."
"Under the circumstance, the national sentiment will not accept signing a military pact with Japan," Kim said by telephone.
The Korean Council for the Women Drafted for Military Sexual Slavery by Japan released a statement demanding a cancellation of the agreement and an apology from the government.
"The government has caused more offense to the victims of sexual slavery than even the right-wingers of Japan," the council said, urging the government to work harder to settle Tokyo's colonial crimes.
The pact does not need parliamentary approval from the two nations, ministry officials said.
South Korea currently has similar military deals with 24 countries, including the U.S., Canada, Britain, Australia and Russia.