A secret weapon has rid Christchurch city centre streets of crime and thuggery: Mozart.

The introduction of speakers playing classical music in City Mall in June 2009 has led to a steep fall in petty crime and anti-social behaviour, say mall managers.

The figures are staggering:

The number of anti-social incidents attended by city centre security guards, known as ambassadors, fell from 77 a week in October 2008 to two for the same week this year.

The number of drug and alcohol-related incidents fell from 16 in 2008 to zero this year.

The number of times the ambassadors helped shopkeepers with troublesome customers has fallen from 35 to nothing.

Originally, Central City Business Association manager Paul Lonsdale intended to play easy listening music like Barry Manilow, but found classical music more calming.

"The classical music is soothing on the ear. We try not to play anything with a beat because that is more noticeable. Classical music is known for reducing anti-social behaviour," he said. "It is much more pleasant now. People sit in that area now because they feel safer."

The statistics include all incidents attended by the ambassadors between Oxford Tce, Manchester, Hereford and Lichfield streets, but most incidents were in City Mall. The ambassadors were introduced in September 2007.

Senior Sergeant Gordon Spite, officer in charge of the city centre police beat section, said the music has helped transform the mall.

"The music has certainly had an effect during the day. It has created an environment that is conducive to good behaviour," he said.

"If you go into an area that is uncared for and knocked around there is a clear message that no-one cares and you can do what you like. There are no rules. The music has had quite a calming affect on things. A more diverse group of people use it now than before."