The personal information of customers whose identification is scanned at Kings Cross nightclubs could end up in the hands of criminals with ties to the venues, privacy advocates are warning.

A 12-month trial of linked identity scanners is due to begin for ''high risk'' pubs and nightclubs in Kings Cross in time for the peak summer trading period.

Forced to provide personal information: A security guard scans IDs as patrons enter a nightclub. Credit:Wayne Taylor

Late trading venues with a capacity of more than 120 people will be forced to scan their customers' photo ID - most likely a drivers licence - and store the details for a maximum 30 days.

The state government plan is designed to prevent patrons who are thrown out of one establishment entering another and enforce new ''precinct banning orders'' for repeat troublemakers.