The largest Kings Cross hotels and nightclubs will have to scan the identification of customers every night of the week and for 24 hours on Fridays, weekends and public holidays under rules designed to reduce alcohol-fuelled violence.

Hoteliers had been pushing to restrict the system - whereby patrons must have photo ID scanned upon entry - to Friday and Saturday nights and only for venues with a history of violence.

Desperate need for change: The death Thomas Kelly, an innocent victim of alcohol-fuelled violence, has increased awareness about the need to make Kings Cross a safer place.

But hospitality minister George Souris will announce the state government plans to implement the system for the majority of opening hours and for all venues with a capacity of 120 or more that trade past midnight.

The decision means scanners will be in operation at 35 venues in Kings Cross from 7pm on Thursdays until 7am on Mondays and between 7pm and 7am on Mondays, Tuesdays and Wednesdays.