Tokyo (AFP): A Japanese regional court on Thursday ruled the country's failure to recognise same-sex unions an "unconstitutional situation", offering hope to campaigners who have brought a series of lawsuits with mixed results.

The ruling by the court in southern Fukuoka rounds off the first stage of a coordinated legal battle launched by LGBTQ campaigners in 2019.

More than a dozen couples filed claims in five district courts, seeking damages from the state for preventing them from getting married.

None of the courts upheld the requests for compensation, but judges were split on the question of whether Japan's lack of marriage equality violates its constitution.

That has given campaigners in the only Group of Seven country that does not recognise same-sex unions some hope, said Takeharu Kato, a lawyer who brought a case in northern Sapporo.

All the courts "at least agree on the need for legislation that publicly endorses the relationships of same-sex unions and grants them legal protection equivalent to heterosexual couples", he told AFP.

Thursday's ruling in Fukuoka echoed an earlier decision by Tokyo's district court, finding that the lack of marriage equality amounts to an "unconstitutional situation", while stopping shy of declaring it an outright violation.

"Current laws that don't grant same-sex couples ways to legally become family with the partners of their choice represent an unconstitutional situation" in terms of "individual dignity", the court said.

Polls show the majority of Japan's public backs same-sex marriage, while a growing number of employers and municipalities including Tokyo now offer some of the same benefits to same-sex couples as married ones.

The 1947 constitution says marriage requires "the mutual consent of both sexes" -- but it also states that all people "are equal under the law".

"The government does not consider the Civil Code and other provisions on marriage to be contrary to the Constitution," top government spokesman Hirokazu Matsuno told reporters last week after a court in the central city of Nagoya issued a ruling.

'What we want is marriage'
That verdict called the current situation unconstitutional, saying same-sex couples are "excluded from important personal benefits bestowed on legally married couples".

"The rationale for allowing these large disparities to exist, and taking no action to redress them, is now shaky," the Nagoya court said.

Sapporo's district court, like Nagoya, called not recognising same-sex marriage unconstitutional.

However, Osaka's district court found the opposite, arguing discrepancies between same-sex and heterosexual couples were already being addressed in part by partnership certificates issued by municipalities.

Kato said all the rulings sent a message that same-sex couples are entitled to legal protection.

However, the courts left open whether the rights of same-sex unions can be safeguarded by systems that stop short of marriage, such as the partnership licenses.

Appeals are expected against several of the rulings, and plaintiffs plan to push back against the argument that alternatives to marriage offer them equal rights, Kato said.

"What we want is marriage."

The latest ruling comes as Japan's parliament edges closer to passing new legislation on "promoting understanding" of LGBTQ rights.

The proposed bill says "unjust discrimination" towards sexual minorities must not happen, with the word "unjust" added to a previously mooted version of the legislation.

Activists have dismissed the legislation as a "meaningless gesture" because of the watered-down language.