Australian federal and state police are ordering phone providers to hand over personal information about thousands of mobile phone users, whether they are targets of an investigation or not.

Fairfax Media has confirmed Australian law-enforcement agencies are using a technique known as a "tower dump", which gives police data about the identity, activity and location of any phone that connects to targeted cell towers over a set span of time, generally an hour or two.

Data concerns: Law enforcement agencies are conducting 'tower dumps' to find criminals. Credit:Robert Rough

A typical dump covers multiple towers, and mobile providers, and can net information about thousands of mobile phones.

The dumps are usually used in circumstances when police have few leads and can be a useful, powerful tool in tracking down criminals. But privacy advocates say that while they may be helpful to police, they also target thousands of innocent people and don’t have any judicial oversight.