Blackface is a form of theatrical make-up used predominantly by non-black performers to represent a caricature of a black person.
It originated in the United States in the early 19th century when it was used in minstrel shows. These featured comic skits, music and dancing to mock people of African descent.
Harcourts chief executive Chris Kennedy told Stuff the group were told that others at the party were offended by the black makeup. "As there was no intention to offend they were responsive to the concerns and left."