A UNITED States governor has been urged to resign over a racist photo in which he appeared more than 30 years ago.

Virginia governor Ralph Northam appears to have almost no choice but to leave office after losing support from virtually the entire state Democratic party and other key allies.

The calls for Northam to step down came in a wave after the Democrat had apologised for appearing in a photo in which one person is dressed in blackface and another is wearing a full Ku Klux Klan uniform.

The photo appeared in his 1984 medical school yearbook.

In his first apology, Northam called the costume he wore “clearly racist and offensive”, but he did not say which one he had worn. He later issued a video statement saying he was was still committed to serving the “remainder of my term”.