TOKYO, Mar. 14 (Reuters) - Japan's bar on same-sex marriage is unconstitutional, the high court in the northern region of Sapporo said on Thursday, the first such ruling by an appeals court on a matter that has divided the lower levels of the judiciary.

While Japan is the only Group of Seven nation without legal protection for same-sex unions, the ruling by the Sapporo High Court dismissed the plaintiffs' claim for damages from the government.

"I thought the ruling might be a conservative one, but it ended up exceeding my expectations," one of the plaintiffs, who did not disclose his name, told reporters after the ruling. "I couldn't help but cry."

The debate whether Japan's laws against same-sex marriage are unconstitutional has split lower courts, with one district court holding the bar to be constitutional but others saying it is unconstitutional in varying degrees.

Although opinion polls from 2023 show about 70% of the public backs same-sex marriage, the conservative Liberal Democratic Party of Prime Minister Fumio Kishida opposes it.