The LDP plans to reprimand three senior party members for refusing to participate in the House of Representatives vote last month on the Self-Defense Forces dispatch to Iraq, informed sources said Tuesday.

The three who broke with the Liberal Democratic Party's policy of backing the decision of Prime Minister Junichiro Koizumi are Koichi Kato, Makoto Koga, and Shizuka Kamei.

Kato and Koga are both former LDP secretaries general, while Kamei is a former party policy chief.

Shinzo Abe, the current secretary general of the LDP, is tasked with deciding their punishment.

He will reprimand them Thursday, according to the sources.

Kato and Koga walked out of a plenary session shortly before the Lower House voted on the dispatch of the SDF to Iraq in the early hours of Jan. 31. Kamei did not show up at all.

Kato later told reporters he believes it is inappropriate to send the SDF to Iraq because there was no reason for the U.S.-led war on Iraq in the first place.

The punishment will be an official warning from the party, the second-lightest form of punishment issued on the authority of the secretary general.

Some LDP members insisted on harsher punishment, such as suspension from their party posts, in light of the difficult position of the LDP's junior coalition partner, New Komeito.

New Komeito backed the dispatch despite strong opposition from its members and supporters.

But Abe decided on a lighter punishment, fearing that a crackdown would cause instability in the party's balance of power.