Contraband items worth over €910,000 has been seized at a premises in Burnfoot, Co Donegal.
More than 530,000 cigarettes and tobacco products were discovered as well as cash valued in excess of €410,000.
Two vehicles, a cash-counting machine, financial documentation and mobile phones were also seized in a joint operation involving gardaí and Customs Service.
A Revenue Commissioners spokesperson said: "The illicit cigarettes, of various brands, and tobacco, branded 'Flandria Virginia', have an estimated retail value of over €496,000 representing a potential loss to the Exchequer of approximately €392,000."
Revenue officers were granted a three-month cash detention order by Judge Éiteáin Cunningham at Buncrana District Court.
The cash seized includes €124,700 and £242,315 (worth approximately €290,300).
It is suspected the money is the proceeds of, or intended for use in, criminal activity.
The intelligence-led operation was conducted with the assistance of the Donegal Division of An Garda Síochána, and a number of individuals were questioned.
On Wednesday, contraband seized included over 338,000 cigarettes, 12.4 kg of rolling tobacco, approximately €415,000 in cash and two vehicles.
A further 200,000 cigarettes were seized during the course of follow up searches today.
A spokesperson for An Garda Síochána said: "Gardaí are investigating suspected money laundering offences contrary to the Criminal Justice (Money Laundering and Terrorist Financing) Act, 2010.
"No arrests have been made at this time. Investigations are ongoing."
This seizure of contraband worth more than €910,000 is part of Revenue’s ongoing operations targeting the supply and sale of illegal cigarettes and tobacco in the shadow economy.
The cigarettes seized were branded Lambert and Butler Original, Lambert and Butler Silver, Manchester Red, Gold Mount, Mayfair, Benson & Hedges Silver, Regal King Size, Richmond King Size, Superking Black, Excellence and Yett Virginia.
A Revenue spokesperson said that "if businesses, or members of the public, have any information regarding the smuggling or sale of illegal cigarettes or tobacco, they can contact Revenue in confidence on 1800 295 295."
