A Japanese court has rejected a damages lawsuit filed by a person who was denied the right to receive spousal benefits for a same-sex partner.

The Sapporo District Court on Monday handed down the ruling on the lawsuit against the Hokkaido prefectural government and a mutual aid association for local government workers.

The plaintiff, Sasaki Kaoru, is a former employee of the Hokkaido government. Sasaki, whose gender was recorded as female at birth, identifies as non-binary.

Sasaki used the framework provided by Sapporo City that effectively recognizes same-sex couples, and lives with a partner.

In 2018, Sasaki applied to the prefecture and the association for benefits including a dependency allowance, but was rejected on the grounds of being in a same-sex partnership.

Sasaki argues that the rejection violated the Constitution that guarantees equality under law, noting that spousal benefits are paid to common-law heterosexual couples.

The defendants say a civil partnership is presumed to be between heterosexual people.

Presiding judge Migita Koichi said there was no illegality or negligence in the defendants' responses.

A lawyer representing Sasaki says the trial is the first in Japan to argue that a partner in a same-sex relationship should be recognized as a dependent.