Homelessness campaigner Peter McVerry has called for increased investment in drug treatment to help reduce crime in Dublin city centre.
Fr McVerry was responding to a recent announcement of €10 million extra funding for garda overtime in the capital.
The funding follows a number of high-profile attacks on tourists in the city so far this year.
Speaking on RTÉ's Drivetime, Fr McVerry, said: "I work with a lot of drug users and every drug user I've ever worked with comes to a point in their life where they want to come off drugs.
"And when they get to that point, you have a small window of opportunity to help them, but if they go on a waiting list of three, four months or even longer, they become demoralised.
"They get fed up, they feel this is not going to happen. So, it's the frustration of shortage of our places for addiction treatments.
"70% of those who go to prison as you say, have an addiction.
"About 80% of all monetary crime is drug-related, people robbing to pay for their drug use or people robbing to pay off drug debts.
"And many other types of crime like criminal damage or assaults are also drug related."
He said if Ireland wants to reduce crime it needs to invest in drug treatment.
Fr McVerry added that it is "already very expensive not investing in drug treatment" as every prisoner costs the taxpayer €80,000 a year.
'What happens at the end of the year?'
The campaigner said he has no problem with extra garda overtime, but asked "what happens at the end of the year?".
"We're back to square one unless we want to spend another €25 million next year on garda overtime," Fr McVerry said.
"Because spending money on drug treatment services has a long-term effect. Garda overtime has a temporary effect.
"On average, a drug user might rob twice a day to feed a fairly bad drug habit. Somebody goes on a three-month waiting list to get into drug treatment that's 200 crimes committed.
"So, getting crime down, essentially it seems to me means dealing with the demand for drug treatment."
Also speaking on RTÉ's Drivetime, cafe owner Stephen Kennedy welcomed the move to increase garda overtime.
"I would very strongly advocate for more to be done to provide support services to individuals who are chronically and acutely addicted to drugs," he said.
"But certainly, we also have to address the situation that is happening on the streets right now, which is organided gangs dealing on an industrial scale very openly on the corner of Aston Quay and right throughout Temple bar."
However, he agreed that more needed to be done and a more permanent solution put in place.
"No one garda station can solve the issue of drug dealing and street crime that has become so complex, and so extreme," Mr Kennedy said.
"So there needs to be a coordinated response. It needs to be targeted; it needs to be separately resourced."
