Japan's parliament has approved joining an international child custody treaty amid foreign concerns that Japanese mothers can take children away from foreign fathers without recourse.

The upper house of parliament voted Wednesday to join the 1980 Hague Convention on international child abduction following passage by the more powerful lower house last month.

The convention seeks to ensure that custody decisions are made by the courts of a country of abducted children's original residence and that the rights of access of both parents are protected.

Japan will likely join the convention within the fiscal year that runs through March 2014 after parliament passes an implementation bill and various other procedures are put in place, according to Tatsushi Nishioka, a Foreign Ministry official.