The trio fled in a stolen dark-blue Mazda Familia hatchback before dumping the getaway car nearby in a residential area. They then jumped into a second vehicle, Greenstreet said.
"This was a violent and dangerous incident and it is fortunate further people were not serious hurt," he said.
Police are asking anyone who witnessed the hold-up or has information about the incident to call Christchurch Police on (03) 363 7400 or anonymously via Crimestoppers on 0800 555 111.
It's at least the second time the pub has been targeted by armed raiders, with gun-toting robbers making off with cash in 2014.