Wellington police have arrested almost 600 people this year for breaches of the inner city liquor ban.
Emergency response manager Inspector Simon Perry says the ban has virtually cleared the city streets of drunken and sometimes abusive vagrants.
He says it's harder to quell regular weekend disorder, which has only decreased slightly, but if even a few people are saved from drunken violence, the ban is worthwhile.
Inspector Perry says other factors could also have contributed to the fall in reported crime, including the anti-violence programme "It's Not OK", and environmental changes such as better street lighting.
In Christchurch, where 1100 arrests were made during the year for liquor ban breaches, police say the arrests have helped lower the level of reported serious crime.
Police tactical co-ordinator Senior Sergeant Philip Dean says by acting on disorder and liquor ban breaches early, more serious crime is prevented.