Dog owners who walk more than four pets at a time face a fine of up to £100 from today.
Owners must also prove they have something to pick up dog mess with and agree to put their pets on leads if asked to.
The new rules are part of a raft of new measures imposed by Gosport Borough Council in Hampshire - but other councils may follow suit.
Cllr Graham Burgess, Chairman of the Community Board, said: "We understand that some dog owners and walkers did not support this, but we've had recent feedback from the public in general that has been in support of it.
"We know most people who own or walk dogs are responsible. The rules are aimed at the minority who aren't.
"We hope responsible people will tell us if they spot someone breaking the rules."
Owners who pay straight away will get a £50 reduction on their fine but failure to pay could result in court action.