Police shot a man and his partner at an erotic costume party at a King Street nightclub, despite having been told the gun he was toting was a plastic toy, a court has heard.

Dale Ewins and Zita Sukys had just been engaged in a sex act at the fancy dress Saints and Sinners ball at the Inflation club on on July 8, 2017, when officers surrounded them and opened fire, using hollow-point bullets.

Dale Ewins leaves court on Monday. Credit:AAP

Mr Ewins was toting a toy pistol he bought at a $2 shop and sported a fake tattoo across his forehead, likening him to a serious criminal, the opening day of a Supreme Court trial was told on Monday.

Earlier in the night, he had jokingly pulled the fake gun on the barman in a bid to avoid paying for his drink and video footage played to the court showed laughter ensued.