Crack is the street name given to a solid form of cocaine that is usually smoked.
Daithi Doolan, from the South Inner City Drug and Alcohol Partnership, said many homes in Dublin had some form of addiction.
“It’s actually a crisis,” he added.
“It’s happening at the school gate in the playground.”
Doolan, who is also a Sinn Féin councillor, said communities cannot cope with the scale of drug use.
“The drug-related intimidation is affecting individuals, families and whole communities are being held to ransom by the drug dealers.”