Last financial year nearly 2.5 million checks were made against the system, an average of almost 80,000 a day. Email addresses and associates of ''persons of interest'', information about gun owners, stolen cars and missing people - and their next of kin - is also to be added. The database, accessible to the nation's 50,000 police officers, also holds photographs of 2.8 million people, and another holds the fingerprints of 3.1 million - nearly one in five adults in the country. In other records police can find every listed telephone number and address, anyone licensed to own a firearm or dangerous chemicals, and more than half a million DNA records. Most people charged in NSW are fingerprinted, but only those facing more serious charges have a DNA sample placed on the national database, though samples need to be destroyed if people are acquitted or trials have not started within 12 months. All this data is held or hosted by the little-known national organisation CrimTrac, which brokers police information.

But the president of the NSW Council for Civil Liberties, Cameron Murphy, said privacy safeguards had not kept pace with the increase in information available to police forces. ''I just don't have any confidence in the integrity of it. … We should be worried because there's a potential for information to be misused when it's kept and stored in this manner.'' While he said he was aware only of minor complaints so far, Mr Murphy said the European Union would not share some information with Australia because of concerns about inadequate privacy laws. But CrimTrac, which has won several IT awards, was a finalist in last year's Australian Privacy Awards. Its chief executive, Ben McDevitt, said the organisation took data security and privacy seriously and could audit all access to the system. ''Wherever privacy and technology interact, there are privacy issues … No system has zero vulnerability. All we can do is be very conscious and have the best systems,'' he said.

CrimTrac was also using sophisticated data matching software to detect identity theft, he said. ''The ability to identify individuals uniquely and unequivocally is absolutely core to the criminal justice system,'' he said. Biometric tools such as DNA and fingerprints were particularly powerful tools to establish a person's identity. Having national warnings about possible violent suspects available meant that police could react more appropriately to those they encountered on patrol, said NSW Assistant Commissioner Carlene York. A gradual introduction of hand-held computers also meant the information was increasingly accessible on the streets, saving time. Mr McDevitt said: ''Their [police officers'] job is difficult enough as it is. We do the best we can to give them timely and accurate information.''

While he has ruled out a merger of all its databases, he said the NPRS would ''adapt to the changing needs of police''. Plans include facial recognition technology for the photos of offenders and missing people; cross-checking information about crimes in various states to find links among different offences; number plate recognition; links between the finger print system and records of detention centres; exchange of criminal history information with New Zealand and Britain; and a database of photos of child pornography and exploitation.