More than 400 cannabis factories have been uncovered so far this year following the discovery of another five grow houses this week.
Garda Commissioner Martin Callinan said that the eight-week harvesting period for a cannabis crop provided "a conveyor belt of money" to gangs.
The trade is dominated by Vietnamese and Chinese gangs, while Irish criminals have also become involved.
Mr Callinan said the nu-mber of growhouses being found in recent years was a "continuing worry". He said the 400-plus factories hit this year was "definitely up" on 2011, which was a high on previous years.
He was commenting on the back of the seizure of an estimated €3.5m worth of plants seized from factories in six locations this week. It follows the seizure of €5m worth of plants from four industrial-style grow houses last month.
The raids on growhouses in Sligo, Cork, Wexford, Meath, and Dublin were part of a massive nationwide operation targeting criminal gangs and criminals involved in drug dealing, firearms offences, burglaries, and other property crime. A total of 113 people were arrested.
Gardaí said the arrests were for drug trafficking, robbery, aggravated burglary, having firearms, burglary, theft, handling stolen property, and other offences.
Source: Cormac O'Keefe, Irish Examiner, 23/11/2012