TOKYO - A system to register same-sex partnerships opened for applications in Tokyo on Tuesday, in a symbolic step forward for a country that has fallen behind its peers on embracing diversity.

The system does not offer the legal benefits of marriage for same-sex couples, but has been welcomed by LGBTQ rights groups as a small step forward.

Japan is the only Group of Seven major democracy not to allow either same-sex marriage or civil unions, despite polls showing that the public is largely in favour of the change.

"The introduction of the system in Tokyo is extremely positive," said LGBTQ rights activist Soshi Matsuoka. "But partnership is not enough. We basically want legal marriage."

With its own population ageing and rapidly shrinking, the lack of such provisions could damage Japan's ability to compete for talent against the dozens of countries that have legalised marriage equality, industry bodies have warned.

Nonetheless, Prime Minister Fumio Kishida, the leader of the conservative ruling Liberal Democratic Party, has urged caution on the issue.

Tokyo is influential

The system is open to couples of whom at least one partner lives, works or studies in Tokyo, and where both are at least 18 and are not already married or in a partnership.

Applications are to be made online, and certification will be available from Nov 1, according to the Tokyo Metropolitan Government website.

"What I've wanted for so long now feels real and I'm happy," Ms Soyoka Yamamoto, 37, told reporters, tearing up after she and Yoriko, her partner of 11 years, submitted their applications online at a news conference in central Tokyo. "We can now be recognised by society as a couple."

The two planned a family celebration later, she said.

Registered couples would be entitled to apply together for local government services, such as public housing in the capital.

An online handbook explaining the system noted that some private-sector firms provide family benefits to employees in same-sex relationships, and services like family credit cards and mobile phone discounts to customers in such partnerships.

While local government partnership certification systems have already been introduced by dozens of municipalities, including some in the capital, Tokyo accounts for more than 10 per cent of Japan's 125 million population, and its policies have a bigger impact.

"In terms of deepening understanding and respecting LGBT rights, Tokyo is very influential, so this is a wonderful thing," said Mr Hiroshi Ikeda, a campaigner with Marriage For All Japan.

He sees the partnership recognition system as a lever to press the central government for progress.

Still a long way to go

Same-sex couples often face exclusion from medical decision-making, difficulty in renting accommodation and lack inheritance rights.

"In the end, there are a lot of things we won't be able to do unless the central government changes laws," he said.

While attitudes among the general public toward same-sex marriage have turned increasingly positive in recent years, some conservative politicians continue to show hostility to the idea.

Mr Noboru Watanabe, an LDP assemblyman in Aichi prefecture, was forced to apologise earlier this month after a social media post calling same-sex marriage "disgusting", the Mainichi newspaper and other media reported.

Plaintiffs have met with mixed fortunes in a series of legal cases challenging Japan's position not to recognise same-sex marriage. Last year, three couples won a partial victory when the Sapporo District Court found that same-sex couples' lack of access to some of the rights afforded by marriage amounted to discrimination.

By contrast, an Osaka court ruled against marriage equality in a separate case in June. Another case last month found that refusing residency rights to the US-national same-sex spouse of a Japanese citizen was unconstitutional. The two were married in the US. BLOOMBERG