Stolen handguns are selling for more than $1000 on the black market in Christchurch and shotguns and rifles for hundreds of dollars.
They have become an item of choice for burglars who are targeting homes where they know there are firearms.
Police say the illegal drug trade is fuelling the need for criminals to arm themselves and gangs are key players.
Police have set up a 35-strong task force to combat the problem.
Since March police have searched 175 properties in Canterbury, recovered 87 firearms, and seized more than $5 million of assets related to criminal offending.
Two more properties were raided in Bromley and Halswell yesterday, where firearms and drugs were found. Two men were arrested.
Police didn't have figures late yesterday as to how many firearms have been stolen in Canterbury in recent months.
The Christchurch Star revealed that last month alone more than 30 firearms were stolen from Greenpark, Leeston, Lower Styx and Avonside. They included high-powered rifles, shotguns and .22 calibre rifles.
Canterbury University criminologist Professor Greg Newbold said handguns were going for more than $1000 on the black market because they were relatively difficult to obtain.
"Shotguns and .22 rifles are the most commonly used in crimes and can be brought for a couple of hundred dollars. Pistols can be over $1000," Newbold said.
Gun owners needed to store firearms securely, he said.
"Guns are pretty hard to steal when they are stored properly. If they are being stolen from rural properties I would suggest they are not being stored correctly."
The task force includes officers who work to combat gangs and hardened criminals responsible for a large proportion of crime in the city.
District police commander Superintendent John Price said the task force was targeting the top 2 per cent of criminals committing 20 per cent of crime in Canterbury.
Recent gun thefts
• June 10: Eighteen firearms stolen from a Greenpark property.
• June 15: A .303 and .270 rifle and two shotguns were taken from a Leeston property.
• June 22: Shotguns stolen were stolen from Lower Styx.
• June 24: An Avonside property was broken into and about six firearms were taken.