Up to 5,800 cannabis plants worth about €4.6m have been seized during a series of raids.
Eight men are being questioned over the discovery of six growhouses at industrial units and commercial premises across the country yesterday.
Gardaí said the searches were carried out as a part of Operation Nitrogen, an intelligence-led operation by the Garda National Drugs Unit targeting the cultivation of cannabis.
The suspects, who are believed to be from Asia, are being questioned at various Garda stations across the country.
* Four men were arrested when a large cannabis cultivation operation, with about 1,700 cannabis plants with a rough street value of €1.36m, pending analysis, were found in an industrial unit on Connaught Rd in Longford.
* About 1,000 plants, worth €800,000, were discovered in an industrial unit at Cornafulla, Athlone, Co Westmeath. One man was arrested by gardaí at the scene.
* A search of an industrial site in Drogheda Business Park, Co Louth, uncovered 1,600 cannabis plants with an approximate street value of €1.28m. Two men were detained.
* One man was taken in for questioning when 1,000 plants, worth about €800,000 were found at a commercial site in Campile, Co Wexford.
* In and industrial unit in Kiltimagh, Co Mayo, 500 plants, with an estimated street value of about €400,000 were seized. There were no arrests.
* Elsewhere, cultivation equipment was seized in a residential house in Foxborough Hall in Lucan, Co Dublin. No plants were found.
All the suspects can be detained for up to seven days under Section 2 of the Criminal Justice (Drug Trafficking) Act, 1996 as amended.
© Irish Examiner Ltd. All rights reserved