The three men in balaclavas stormed into the Lucky Star Tavern at Sunnybank Hills on Monday and held staff and customers at gunpoint.
They forced them to lie on the floor and revealed a bundled item they said was an explosive.
“The men then placed an item on the bar, claiming it was explosive,” a police spokesperson said.
“The item was later identified as cakes of soap taped together.”
The gunmen, one armed with a hand gun, and another with a shotgun, demanded a staff member to open a safe, then they legged it out of the pub with cash.
One of the robbers was wearing a black balaclava and black shirt and had a hand gun, another was wearing a black balaclava, black shirt and light-coloured tracksuit pants, and a third was wearing a black balaclava, a light-coloured shirt and trousers, and was carrying a grey sports bag.
Police would like to speak to anyone who may have seen the men constructing their soap ‘bomb’, or leaving the car park of the Hellawell Road Hotel at the time of the robbery.