A ban on hoodies covering faces has been introduced in parts of Sefton in a bid to combat anti-social behaviour and organised crime.
The Public Spaces Protection Order (PSPO) applies to parts of Bootle and Litherland.
The new power, brought in by Sefton Council, was a response to "high levels" of anti-social behaviour in the area, said a spokesman.
Groups of two or more causing trouble will be separated, it added.
The order covers areas including parts of the Leeds & Liverpool canal and along Merseyrail's Northern line.
The PSPO rules that:
- Heads and faces must not be covered by hoods or other face coverings (except cultural items of clothing)
- Mechanically-propelled vehicles must have a vehicle registration plate
- All dogs must remain on leads
- Groups of two or more will be dispersed if they are causing trouble
Councillor Trish Hardy, cabinet member for communities and housing, said: "The majority of people who live here are good, law abiding citizens, but unfortunately we have been struggling with some high levels of anti-social behaviour.
"What we are attempting to do is help police tackle people causing problems and the community also gets reassurance that there is an active police presence happening."
She said the "strong and vibrant neighbourhoods" in Bootle and Litherland would find the the PSPO's introduction "positive".
The council will work with Merseyside Police to implement the order.
Police Commissioner Jane Kennedy said she welcomed Sefton's decision to take a "firm stance" by introducing it.
Sefton Council has already introduced a dedicated anti-social behaviour officer.