Shrewsbury Police issued the order to cover this weekend.
It allows police to tell people to leave an area. If they refuse they face arrest.
Sergeant Rebecca Thomas said the order had been agreed after anti-social behaviour issues last weekend.
She warned that any people who cause further disorder will be dispersed.
Writing on Twitter, she said: "There is a section 34 dispersal order in place around Shrewsbury town centre in order to prevent some ASB issues encountered last weekend. Offenders will be dispersed if causing disorder."
The orders can last for 48 hours and can be used in a number of scenarios, such as when an inspector may have intelligence to indicate that there is likely to be anti-social behaviour in a particular park or a housing estate.
The maximum penalty for failing to comply with the order is a £2,500 fine and/or three months in prison.