Youngsters will be banned from venturing out at night without their parents in parts of Sutton Manor blighted by anti-social behaviour.
The controversial move - which came into force on Monday - is part of sweeping new powers being handed to police in a bid to combat yobs on the troubled Chandlers Way estate.
Police chiefs have also obtained a dispersal order covering the same area meaning they can ‘move on’ groups of two or more people if they suspect them of causing trouble.
Both orders will last until January next year.
Insp Elaine Collins said the decision to apply for the powers followed complaints by residents and business owners.
She added: “We have listened to the concerns raised by the local community and businesses and are taking positive action to address anti-social behaviour.
Under the new power, police, community support officers and traffic officers will be authorised to order groups of leave the designated area.
Anyone caught flouting such an order faces arrest. Anyone under aged 16 is also barred from going out on the estate between 9pm and 6am unless they are with a responsible adult.
Insp Collins, however, insisted the powers will not affect ordinary folk.
She said: “This order is part of a range of measures we and our partners are taking to tackle the problems caused by anti-social behaviour in St Helens and should make a real contribution towards making the area a safer place to live and work.”
The area covered by the new power includes the following roads: Jubits Lane to Forest Road, Forest Road to Delamere Avenue, Delamere Avenue to the boundary fence of the King George V playing fields, Boundary fence of the King George V playing fields to Jubits Lane.