The Lower House on Tuesday unanimously approved ratification of signing an international treaty to help settle cross-border child custody disputes, paving the way for passage through the Diet in late May.

The 1980 Hague Convention on the Civil Aspects of International Child Abduction sets out the rules and procedures for the prompt return of children under the age of 16, taken or retained by one parent following the failure of an international marriage, to the country of their habitual residence if requested by the other parent.

The Lower House is set to soon endorse a related bill stipulating the process for the children to return to their habitual residence, setting the stage for the legislation to clear the Diet in late May.

Under the Constitution, a treaty approved by the Lower House will receive Diet approval if the Upper House does not vote on it within 30 days.

A central authority to be established in the Foreign Ministry will locate children upon request. It will ask for the cooperation of local governments and police when necessary.

Exemptions for returning a child will be given in cases of child abuse or domestic violence, according to the bill.

Japan is the only nation among the Group of Eight yet to join the pact, which has 89 signatories.

The United States has been urging Japan to join the treaty as soon as possible, and Prime Minister Shinzo Abe told President Barack Obama in February that Japan was close to accepting the rules of the treaty.