"I highly appreciate it," Defense Agency chief Yoshinori Ono told reporters.

Chief Cabinet Secretary Hiroyuki Hosoda said Japan "welcomes the clear announcement on the size (of troops) and ideas."

Defence Secretary Geoff Hoon announced on Thursday that Britain is to send an extra 220 troops to Iraq to take over from the Dutch forces set to return home in March from Muthanna province.

"Good progress" has been made training Iraqi security forces in the region, meaning British military chiefs believe only 600 foreign personnel are needed to replace the 1,400-strong Dutch contingent, Hoon said in a statement.

Hosoda, the Japanese government spokesman, said Tokyo did not believe the reduced size in personnel would be problematic in maintaining security.

The size of the contingent "must be based on reasonable grounds" and Britain knows the Iraqi situation well, Hosoda said.

Japan, a major US ally, has some 550 troops in the southern Iraqi city of Samawa on a non-combat, humanitarian mission in Japan's first military deployment since 1945 to a country where there is active fighting.

Japan's US-imposed constitution bans the use of force and the right to keep a military, meaning that the troops in Iraq are barred from firing their weapons except in the strictest interpretation of self-defense.

Britain already has around 9,000 soldiers in Iraq, according to defense ministry figures, largely based around the city of Basra in the relatively peaceful south of the country.

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