Domoney said that when they were asked to move, the bar staff were told: "We are the law."
He said that Mitchell accidentally hit a female bar staffer on the side of a head with a glass.
"A female staff member came out of the bar crying and upset and she had said one of the guys from that group which was Clayton had hit her on the side of the head with a glass and spilled his drink on her," he told Newshub.
"It wasn't an assault, it was more of an accidental incident, but it was because he was in that bar area."
Mitchell avoided reporters on his way to the House today, but provided a statement to media.
"We were approached by overzealous pub security who asked my friend and I to leave.
"Apparently we were standing in the wrong place in the pub and had not moved when asked. We were escorted out and left the premises."
Peters said that the bar would show video footage of the incident this coming Saturday night, and that footage proved that Mitchell had not acted inappropriately.
"We are so happy for you to see it that we ask you to turn up on Saturday night, have a good hard look at it, and then tell the public what you think," Peters told reporters.
"If you can't justify it with evidence, stop speculating."
Asked about the accidental contact with the female staffer, Peters said: "You're just scaremongering and making it up as you go along. Why don't you look at the video? That exonerates Mr Mitchell totally."
Peters said he had not seen the video, but he had been told what was on it by someone he had "enormous trust" in.
