The ruling coalition of the Liberal Democratic Party and Komeito agreed Wednesday to hold discussions on the introduction of a dual surname system for married couples.

Prime Minister and LDP President Shigeru Ishiba and Komeito leader Tetsuo Saito reached the agreement during a lunch meeting at the prime minister's office.

However, they stopped short of deciding when to begin discussions on the issue, as Ishiba cited the need to build a consensus within the LDP, according to Saito, who spoke to reporters after the lunch meeting.

Saito quoted Ishiba as saying that he would like Komeito to wait a little more, and that he aims to prepare an LDP proposal on the issue as soon as possible in order to begin talks with the coalition partner.

"We should begin talks in January at the earliest," Saito said.

Meanwhile, during the meeting, Saito urged Ishiba to decide for Japan to participate as an observer in a meeting of the parties to the Treaty on the Prohibition of Nuclear Weapons to be held in the United States in March.

In response, Ishiba said that the government has completed a study of countries, including Germany, that have attended such meetings as observers and will inform Komeito of the results of the study.