A massive case of mistaken identity in the UK is prompting calls for a rethink on plans to use facial recognition technology to track down terrorists and traffic offenders.

Key points: London trial of facial recognition technology generated 102 false alerts out of 104 alerts

London trial of facial recognition technology generated 102 false alerts out of 104 alerts CCTV footage from carnival and rugby matches was scanned for wanted criminals

CCTV footage from carnival and rugby matches was scanned for wanted criminals South Wales trial resulted in 2,400 false positives from CCTV footage

"If you have technology that is not up to scratch and it is bringing back high returns of false positives then you really need to go back to the drawing board," president-elect of the Law Council of Australia Arthur Moses told AM.

The comments follow revelations a London police trial of facial recognition technology generated 104 "alerts", of which 102 were false.

The technology scanned CCTV footage from the Notting Hill Carnival and Six Nations Rugby matches in London in search of wanted criminals.

"What the police were attempting to match with CCTV data was photographs that they've taken while people have been in custody or have been filmed during a crime being committed," said Paul Wiles, the UK Government's Biometrics Commissioner.

Another trial by South Wales police returned 2,400 false positives from CCTV footage gathered at UEFA football matches and the like.

Police officers followed up the alerts, in some cases questioning innocent crowd members who'd been matched by the software with criminal identities.

No one was detained as a result of the software trial.

But Mr Moses said it was still an "invasion of privacy" when innocent bystanders are asked to prove their identity to police because of inaccurate face-matching software.

Legislation currently before the Australian Parliament would allow national security agencies to use driver's licence photos and, potentially, social media images to match with CCTV footage.

The technology would target major crimes like terrorism but also "road safety".

With the high number of false positives recorded in the UK, Mr Moses thinks valuable police resources could be tied up chasing false identities for minor traffic offences.

"That cannot be good for our national security agencies and it cannot be good for the privacy of people going about their day-to-day lives."