CCTV cameras are watching

To the man who tagged the side of the Auckland downtown police station this month: officers have a clear image of your face thanks to their high-tech CCTV cameras dotted around the city.

The station's 28 cameras have contributed to the arrests of 2232 criminals in the past financial year.

They have been crucial for several high-profile cases including tracing the movements of missing Indian student Srikanth Rayadurgam. Hundreds of hours of footage from along Karangahape Rd and Queen St, where Mr Rayadurgam took $250 from a money machine, have been sorted though.

Police also have have footage of a man tagging their station with black spray paint this month, late on a Tuesday night or early on a Wednesday morning.

It's only a matter before they find the person, they say.

The cameras - which can spin 360 degrees, have powerful zooms and can get close enough to read car registrations and detect facial expressions - are monitored on dozens of screens by two non-sworn staff at the Downtown police station's Fort St base. They are running 24 hours a day and all staff have access to them. Staff are able to direct police officers to crimes witnessed on the machines, direct them to crime hotspots before offending has a chance to develop, look for wanted people or to follow cars in a pursuit.

All footage is kept for 21 days - unless it is required for evidential purposes - before being recorded over. Senior Sergeant Ben Offner said about three staff a day requested footage.

The cameras, which are placed at various strategic locations around the inner city, have been there since 2002 but many people don't know they exist, Mr Offner said.

The cameras, which on average need to be replaced every five years, were always being updated and moved to better locations.