A club patron who wrestled a masked gunman to the ground was repeatedly stabbed and remains in hospital with serious injuries.
Police said a man entered the Calwell Club about 2.30am Sunday armed with a gun and demanding people lay on the floor. Police said he tried to take a woman hostage but was stopped by security guards.
Detective Senior Constable Alexandra Uren said a security guard and a male patron chased the man across the road. The patron caught and wrestled the offender but was stabbed several times, leaving him in a serious but stable condition.
"It was certainly very scary for some of the people inside the club," Detective Senior Constable Uren said.
"My advice would be that safety is paramount. It is not worth risking your life when someone has got a weapon."
The man was described as about 180 centimetres tall and Caucasian with a slim to medium build. He was wearing a black balaclava, a dark coloured hooded jumper and jeans.
Anyone with information that could assist police or who may have seen any vehicle in and around the Calwell Club at the time of the attempted aggravated robbery is asked to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website. Quote reference 6047928.