Japanese Prime Minister Fumio Kishida on Saturday sacked an aide for making anti-gay remarks that the prime minister deemed "outrageous".

Kishida said the remarks by Masayoshi Arai, who said he "doesn't even want to see" same-sex couples married, were "outrageous" and "inconsistent" with the inclusive society his government aims to achieve.

"I have taken the decision to remove him from his position as an assistant," he told reporters.

And on Friday, Arai said he "does not like (homosexuals) living near his house," adding that people "will leave the country if we allow same-sex marriage," according to public broadcaster NHK.

Arai, 55, later apologized, explaining that his comments were inappropriate even if they stemmed from his personal opinion.

This dismissal is a new blow to the Kishida government, whose popularity has been declining continuously since last year, after the resignation of 4 ministers within 3 months due to accusations of financial irregularities or association with the controversial Unification Church.

Japan is the only G7 country that does not recognize same-sex marriage.

Its 1947 constitution stipulates that "marriage shall be based solely on the mutual consent of both sexes" and on "equal rights for husband and wife".

On Wednesday, Kishida told parliament that same-sex marriage "may affect society" and that lawmakers should be "very careful in dealing with this issue."

More than 10 couples have filed lawsuits in district courts across Japan, arguing that banning same-sex marriage violates the constitution.

Last November, a Tokyo court said the state's failure to legally protect same-sex couples created an "unconstitutional situation", but at the same time ruled that the constitution's definition of marriage was legal.