Alarmed by ever-louder calls within political circles to revise the Constitution, some 50 Democratic Party of Japan lawmakers set up a study group Monday on foreign and security policy.

Liberaru no Kai said it hopes to present policy proposals by the end of an extraordinary Diet session that will probably be held in the fall. The group was formed by relatively junior members of the opposition party.

Members said they hope to influence intraparty debate on constitutional reform. The DPJ is planning to compile proposals for constitutional revision by the end of the year.

"We are not saying that we should not touch any single word of (the war-renouncing) Article 9," said Yukio Ubukata, a House of Representatives member who is one of the dozen lawmakers collectively leading the group.

"What we are saying is we should try to maintain (the position of) peaceful diplomacy stipulated in Article 9," the journalist-turned-politician said.

"I hope the proposals made here become the mainstream ideas of the DPJ and eventually be realized when the DPJ takes power," he said.

The DPJ contains politicians of diverse ideological backgrounds, including former Socialists, who strongly oppose amending Article 9, and conservatives, who, like many within the ruling Liberal Democratic Party, advocate a constitutional revision that would allow Japan to exercise its right to collective defense.

Liberaru no Kai's charter says the group supports a foreign policy centered on the United Nations and opposes the idea of Japan exercising the right to collective defense, which the charter says could make enemies of certain countries.

It comprises DPJ members who have served less than three terms in the Lower House or two terms in the House of Councilors.