Japan's Prime Minister Kishida Fumio has fired one of his secretaries for making derogatory remarks about same-sex couples. Observers say the issue will be another blow to his administration.

Arai Masayoshi told reporters on Friday that he despises same-sex couples. He later retracted the comment and apologized.

But Kishida dismissed him on Saturday, calling Arai's remarks "outrageous" and incompatible with his administration's policy.

The prime minister said undue discrimination and prejudice based on sexual orientation and gender identity cannot be allowed.

Hoping to minimize the influence of Arai's dismissal, Kishida is expected to explain at the Diet that his government will continue to respect diversity, and aims to bring about a comprehensive society.

The Diet affairs chief of the main opposition Constitutional Democratic Party, Azumi Jun, described Arai's remarks as extremely discriminatory.

He criticized Kishida for lacking the ability to judge appointees, mentioning the dismissal of multiple Cabinet ministers last year, and recent problems caused by his secretaries.

The opposition parties are expected to question the Cabinet's stance on sexual minorities such as LGBTQ. They will also call Kishida to take responsibility for the appointment of unfit officials.