There have been 13 armed robberies in the Christchurch area in the past couple of months and police are investigating whether they are linked.
Five banks, five dairies, two hotels and a pharmacy have been robbed since early May.
In one robbery - at the Glenbyre Tavern in the suburb of Bromley - a shot was fired and is believed to have grazed a patron's forehead.
Detective Inspector Greg Williams says there are similarities between the robberies such as real or fake weapons being used, notes demanding money, facial disguises and stolen getaway vehicles.
But there are also several differences, and he says the police have much work to do.
Mr Williams says while the robbers are stealing only small amounts of money, they could face a lengthy jail sentence if caught.