A Japanese court has ruled the country's ban on same-sex marriage as constitutional - bucking a trend set by courts around the country that had raised hopes for marriage equality in Japan.

The ruling was met with disappointment from plaintiffs and their legal team who had gathered outside the Tokyo courthouse.

Japan is the only G7 country that does not fully recognize same-sex couples or offer them clear legal protection. But it's not an outlier in Asia, where only Taiwan, Thailand, and Nepal offer same-sex marriages.

Ayumi Higashi, the judge who delivered the verdict, said laws on same-sex marriage should first be deliberated in parliament, the Mainichi reported.

Outside the Tokyo courthouse on Friday, the plaintiffs of the lawsuit and their legal team held up signs that read unjust verdict, local media reported.

Shino Kawachi, one of the plaintiffs, told local media that the ruling was difficult to comprehend. Her partner, Hiromi Hatogai, expressed outrage and questioned if the judiciary was supportive, but insisted they would keep fighting.

Amnesty International condemned the ruling as a damaging step backwards on same-sex marriage and called on the Japanese government to take proactive steps towards legalizing marriage equality.

The ruling comes after a series of similar lawsuits were filed between 2019 and 2021, of which five had previously found the ban unconstitutional. This latest exception has deepened the divide in Japan's judicial stance on LGBTQ rights.

The cases will next be taken to the Supreme Court.