The Lower House on Tuesday kicked off much-awaited deliberations on two contentious security bills that would greatly expand the scope of the Self-Defense Forces' missions overseas, and opposition lawmakers immediately went on the attack.

One of the two bills would amend 10 security-related laws and thereby remove some restrictions on SDF operations. One of the revisions would allow Japan to exercise the right of collective self-defense, or the right to come to the aid of an ally under attack.

Opposition lawmakers argued that key passages in the bills are so vague it would allow the government to stretch the interpretation excessively to its own ends.