Three people were arrested and four others hospitalised following what was described as a 'fracas' at Dublin's Forty Foot swimming area yesterday.
Gardaí have appealed for witnesses to the violent incident near the popular bathing area to contact them.
A number of people had reportedly been drinking alcohol at the bathing spot in Sandycove before a row broke out between two groups yesterday evening.
The injured people suffered stab wounds, none of which were life-threatening.
Local councillor for the Dún Laoghaire-Rathdown area, Victor Boyhan, said it was an offence under the council's by-laws to consume alcohol in a public place and he would raise the matter with the council and the Garda.
"For some time now I have been concerned about the high level of alcohol consumption in public places, particularly by young people," Mr Boyhan said.
Local Fine Gael TD Mary Mitchell O'Connor said Sandycove was "a peaceful, family area" and that local community was shocked .
"Despite the fact that there is always a Garda presence in the area, dealing with situations such as this is fraught with difficulty," she said.
Ms Mitchell O'Connor claimed "gangs" often travelled along the coast on the Dart and she believed the activity on the trains should be monitored from the city to the coast.
"Contact could then be made with gardaí in the local area to warn of the presence of gangs in that area."
Three people were held overnight in connection with the incident. Two have since been released while the third remains in custody at Dún Laoghaire Garda station.
Anyone with information is asked to contact Dn Laoghaire Garda Station on 01-6665000 or the Garda Confidential Line 1800-666-111.