He told members of the Oireachtas committee on health and justice that psychoactive substances were a constantly changing phenomenon.
Since legislation was brought in in 2010 to deal with head shops selling illegal highs, about 260 controlled substances have been discovered.
He said: “We are constantly trying to chase and catch up with a very sophisticated and lucrative market.”
He said the Misuse of Drugs Bill, set to be introduced this year, will aim to address the issue. A conference will be held in the Mansion House, Dublin, on July 29 where interested parties can recommend ways to deal with Ireland’s drug problem.
He believes the country cannot wait for a review of the national drugs strategy to focus on what was a very serious problem. “What I hear in different parts of the country is terrifying me,” said Mr Ó Ríordáin.
He told of meeting a 21-year-old man recently who had been addicted to cannabis for nine years.
“That weighs heavily on my thought process when trying to come up with a methodology of having a new drugs strategy,” he said.
“We have a cultural problem in Ireland with addiction. Every family in Ireland has an addiction problem. It is in every corner of the country.”
It is a misconception that the problem only affects certain areas. “That’s not true. It is everywhere. People at a higher income bracket tend to be able to hide it better,” he said.
Mr Ó Ríordáin told the committee there had been an increasing trend towards poly-drug use, involving a combination of alcohol, illicit drugs, and prescription medication.
The national drugs strategy aims to tackle the harm caused to individuals and society by the misuse of drugs through a concerted focus on supply reduction, treatment, rehabilitation, and research.
“The continued disruption of the supply of illicit drugs remains a key priority and this is also reflected in An Garda Síochána’s Policing Plan for 2015,” said Mr Ó Ríordáin.
He said the emergence of new psychoactive substances, specifically designed to circumvent drug controls, had been a matter of particular concern in recent years, both in Ireland and at international level.
Mr Ó Ríordáin said he had met with Mike Penning, the British minister for policing, during a British Irish Council meeting last month. They discussed the practical impact of banning so-called legal highs — the government had introduced a Psychoactive Substances Bill, currently going through parliament, that was modelled on the Irish experience.
“The problem of new psychoactive substances is a constantly changing phenomenon,” said Mr Ó Ríordáin.
“New substances are emerging all the time and we continue to monitor the problem through our national early warning system, which enables the authorities to identify new drugs, describe new trends in use, and report the serious and unusual consequences of drug use.”