Unruly groups could be ordered to leave central Harrow for up to 24 hours under a new 'dispersal zone'.
PCs and PCSOs will be able to force two or more people to leave the area if they are causing harassment, alarm or distress - and detain or arrest them if they refuse or return within a specified time.
The measure, available under the Anti-Social Behaviour Act 2003, will come into force on August 1 for an area bounded by Greenhill Way, Bessborough Road, West Street, Peterborough Road, Kenton Road and Sheepcote Road.
Sergeant Mike Hargreaves, who leads Harrow's Safer Transport Team, said: "It's not a carte blanche to move people on. Lots of anti-social behaviour is showing off to peers so if you can disperse a certain number of the group, the core element, the others will look for something else to do and move away from the vicinity.
"When we disperse people from the dispersal zone, we give them a set amount of time within which they have to disperse and a set amount of time within which they are not allowed to return into the zone. This can be up to 24 hours but will be proportionate.
"They will be given a stop and account form and told how they are expected to disperse: by foot, taxi or bus, for instance."
The discretionary power will enable all officers to move troublesome youths away from Harrow Bus Station in College Road - only PCs can do this at present - but also diffuse nuisance groups of older people on a Saturday night.
Harrow Police took action following a spate of town centre incidents four weeks ago that included several assaults and an assault causing grievous bodily harm.
The zone will run for six months with an option to renew or change the boundaries at the end of that period.
Dispersal zones have previously run in Wealdstone and Harrow town centre before and the police believe that the success in cracking down on anti-social behaviour meant that they were not renewed because there was no longer a demonstrable need for it.