Groups of two or more people around clubs and pubs in Derby are being warned they will be kicked out of the city centre if they cause trouble. Police are invoking new powers from Friday which mean if people do not move on when told, they will be arrested.
Legal notices, which include a map of the area concerned, have been placed around the city.
Officers say the move is designed to make the city centre a more pleasant place to be for everybody.
Derbyshire Police, Derby City Council and the Derby Community Safety Partnership have joined forces under the Anti-Social Behaviour Act 2003 to invoke the Section 30 Order.
It means police officers have the power to disperse people, gathering in the city centre in groups of two or more, if their behaviour is seen to be intimidating or harassing towards others in the area. Chief Superintendent Tony Hurrell, the divisional commander for Derby, insisted this was not an infringement of civil liberties.
He said: "It just gives us the power to first warn people that if you are in the area and we think you are causing intimidation or harassment to people it enables us to ask them to leave the area.
"It's only if they don't leave that we actually will enforce the powers of arrest or other powers we have."
The area covered by the new powers roughly equates to a zone within the inner ring road.