About 300 Maritime Self-Defense Force sailors will leave Friday for Kuwait aboard an MSDF transport ship and a destroyer escort to deliver equipment and goods for troops being deployed to southern Iraq.

It is the latest addition to the Self-Defense Forces' fledgling history of overseas activities that started in 1991 with a mine-sweeping mission following the Gulf War.

Currently, there are about 600 MSDF sailors engaged in refueling activities in the Indian Ocean to help the U.S-led coalition combating terrorism, and 170 more are now en route back to Japan after an annual three-month observation mission in Antarctica.

The 300 sailors going to Iraq will bring the number of MSDF personnel deployed overseas to more than 1,000.

Although participation in these "real" missions may be a morale boost for SDF personnel, who for decades had to be content with just drills, the additional duties are putting a strain on the MSDF's routine operations, according to some officers.

The MSDF is tightening the annual drill schedule -- trying to carry out the same exercise regimen in fewer days -- to make sure all personnel receive the proper training, the officers said.

Regular exercises are necessary to maintain defensive capabilities, because overseas missions are usually peaceful in nature, they said.

The MSDF is also having a hard time choosing the appropriate ship for every new mission from among those not in dry dock or already on other assignments, they said.

"This one-time mission, which will take only about two months (going to and returning from Kuwait), is no problem," an MSDF captain said. "But when asked to perform another long-term overseas mission, I'm afraid we won't be able to keep going."

Since the 2001 enactment of a special law enabling Japan to provide logistic support to the U.S.-led war on terrorism in and around Afghanistan, Japan has kept two destroyers on station in the Indian Ocean to escort a fuel supply ship in three-month rotations.

So far, 6,500 sailors have participated in the antiterrorism operation, or roughly 30 percent of the MSDF's Fleet Escort Force personnel, according to the MSDF.

The Fleet Escort Force, which is in charge of defense missions beyond Japan's territorial waters, comprises 32 destroyers, but about a third of them are usually in port, many in dry dock, for regular maintenance, according to the MSDF.

Plus, current defense policy requires that one of the four MSDF destroyers with the high-tech Aegis air defense system stand ready to head for the Sea of Japan whenever North Korea shows signs of a missile launch.

The limits to the current ship rotation became evident when the MSDF dispatched two destroyers earlier this year to the Indian Ocean for another round of the antiterrorism mission.

Due to the difficulty in finding an available ship, the Myoko left in late January and the Samidare in mid-February, the first time where two destroyers escorting a fuel ship had to leave separately.

Asked how to strike a balance between national defense and international cooperation, Koichi Furusho, chief of staff of the MSDF, said in a news conference last month that he makes decisions with priority on national defense, as required by law.

The 1954 SDF law stipulates that international cooperation activities be conducted "as long as they do not hinder the task of national defense."