A transgender trade bureaucrat on Friday launched a landmark ¥18 million discrimination lawsuit against the government, claiming the trade ministry refused to let her use the female toilets and harassed her about her sex change.

The lawsuit, filed with the Tokyo District Court, exposed what the plaintiff called the bureaucracy's lack of understanding toward sexual minorities and a failure by her employer, the Ministry of Economy, Trade and Industry, to honor its remit to promote diversity among all Japanese firms.

It marks the first time a transgender person has initiated legal action seeking to rectify discrimination at a workplace, her lawyers claimed.