The Mexican Electoral Commission has apologised for an "outrageous" dress worn by an assistant at the first televised debate in the Mexican presidential campaign calendar.

On screen for no more than 30 seconds, model Julia Orayen managed to steal the show in a tight, white dress with a plunging neckline while handing out debate cards.

"We are sorry about the production error associated with the clothing of one of the assistants during the first presidential debate and want to apologise to the citizens and the candidates for the presidency," the Commission said in a statement released today.

The dress was branded an "outrageous stereotype" that overshadowed what should have been a serious event, by Lorenzo Cordova, a member of the Commission.

Many came away from the debate discussing Orayen's attire rather than the political talking points. Even a former Mexican Foreign Minister, Jorge Castaneda, tweeted that "the best was the girl in white and the cleavage at the beginning."

The producer behind the debate, Jesus Tapia, said that in the heat of the moment, no one had checked the assistant's choice of dress before she went on set.

A former Playboy playmate, Orayen was selected as the show's usher due to her height, with Tapia claiming that she was the right height to match the short candidates.

At the time, candidate Gabriel Quadri said that he thought that the girl was "a trap from the (other) candidates".

Another candidate, Josefina Vazquez Mota, said the dress was "not in keeping with the seriousness of the debate".

Watch Ms Orayen's star turn in the video below...