The officers from across the country were in Hobart on Monday night for the 2012 National Police Football Championships, and scores of officers in plain clothes were toasting the start of the tournament.
The police were in another section of the Queen’s Head Hotel, and were unaware of the robbery, Tasmania Police said.
Police said a man who had been playing the poker machines waited until a staff member momentarily left and jumped the counter.
The employee caught him emptying the till of a few hundred dollars, chased the man and was assaulted in the process.
“We have good CCTV footage of the offender and his arrest is imminent,” a police spokesman said.