Micheál Martin has accused the Government of failing to get to grips with the scale of the drugs trade.
The Fianna Fáil leader said that young people and children are being exploited and he called for an all-party approach to tackle the escalating issues.
It comes after a Europol report warned that violence and intimidation from drug gangs have had a severe impact on communities in Ireland.
Mr Martin said the report by the EU Drugs Agency and Europol was “very serious and concerning”.
He said the report illustrates the degree to which violence, death, intimidation, stealing and spreading fear across every community in Ireland, is now a feature and a consequence of a rampant drug trade that is extremely valuable.
“The scale of what is revealed in the report is genuinely frightening and suggests that the state’s response, and the Government’s response to date, notwithstanding the good work of the gardai, is not comprehensive enough to do what we’re currently facing,” he added.
“Provincial towns are now considered most attractive with direct access to local users and new customers, and with very little competition apparently for the big gangs in the provincial towns.
“Young people and children are being particularly exploited.
“I think that is something that we have to be extremely concerned about.”
The report states that organised crime gangs have a three-tier hierarchy structure.
Mr Martin added: “It says at the bottom tier is a large number of highly disadvantaged young people who are often addicts themselves.
“It is this tier, which carries out the bulk of the intimidation, according to your Europol, these typical activities are bullying, assaulting, stealing, vandalizing and spreading fear, on behalf of the network.”
He said that Ireland is now witnessing a rise in the number of children who identify themselves as gang members.
He added: “I don’t think we’re getting to grips with the scale of this issue.”
Mr Martin also called for the Taoiseach Leo Varadkar to accelerate party colleague John Curran’s proposed legislation which would make it a criminal offence to purchase drugs from a person under the age of 18.
Mr Varadkar said that while the Government will examine the Bill, he does have concerns that the legislation may criminalize some children in certain circumstances.
Labour leader Brendan Howlin raised the latest spate of drug-related gangland killings.
“Alongside the murders there’s been a succession of attempted murders, as well as well documented evidence of intimidation, severe violence carried out by criminals involved in drug selling,” Mr Howlin told the Dáil.