An Australian Institute of Criminology report has called for a moratorium on identity scanners in nightclubs, after finding they don't reduce alcohol-related violence and raise serious privacy issues.

On Friday, the O'Farrell government revealed it had been forced to postpone its trial of identity scanners in Kings Cross, due to start last week, after the company chosen by venues to supply the technology failed a government probity check.

Pub scanners in action. Credit:Wayne Taylor

The institute's study of identity scanners in Geelong nightclubs found venues had adopted them to avoid a proposed lockout, but assaults and alcohol-related emergency department admissions had increased since the scanners were introduced.

Violence was ''displaced'' from the 10 high-risk clubs using the identity checks on to the streets, the study suggested.