Violence in Birmingham's clubland could spiral out of control as a result of extended drinking hours, the city council has warned.
Crime in the city centre's Broad Street and Hurst Street, and Sutton Coldfield town centre, could become "unmanageable", the authority said.
The warning was issued by Councillor Talib Hussain, cabinet member for local services and community safety, in response to the Government's consultation on plans to reform licensing laws.
Ministers have argued that scrapping 11pm closing will cut binge drinking and encourage a new continental-style cafe culture.
Staggering closing times is also intended to cut violence by preventing revellers all heading home at the same time.
But the Association of Chief Police Officers has warned that there could be an increase in alcohol-fuelled violence.
In a submission to the Home Office, Coun Hussain (Lib Dem Sparkbrook) said: "I continue to have concerns with regard to the adverse impact of alcohol and alcohol abuse on the citizens of Birmingham."
Coun Hussain warned: "The current capacity and ability to regulate access to alcohol and manage the sometimes anti-social consequences is already a major issue.
"To increase access to alcohol without a stronger regulatory and enforcement framework and capacity would be to risk current situations deteriorating, or even becoming unmanageable."
He also called for more support and protection to be given to taxi drivers.
Conservatives also attacked the reforms, claiming that violence and disease caused by alcohol was already increasing.
Writing in The Birmingham Post today, David Davis, shadow Home Secretary, said: "The only sensible thing for Mr Blair to do now is to postpone the introduction of the new measures until he has got to grips with the problems and there is confidence that liberalising the drinking laws will help, and not hinder, our battle against the curiously British disease of binge-drinking."