More than 100 people who are accused of breaching Derry City Council's by-laws against on-street drinking are to face a formal caution.
It is the first time the council has used the tactic to try and curb public drinking.
The council's Environmental Services Committee chaior, Mark H Durkan, said it was like a "yellow card".
"If an individual is caught in breach of the by-law a second time, then they will be prosecuted," he said.
"We are in unexplored territory here.
"I hope it will prove sufficient deterrent, but if they are found in breach of on-street drinking by-laws again then they will face the full rigour of the law."
A by-law was intoduced in October 2009 prohibiting the consumption of alcohol in any public place.
The PSNI confiscate the alcohol, note the names of offenders and pass the information on to Derry City Council, which has the power to decide whether to prosecute.
Offenders face a maximum fine of £500.