A man from Co Armagh has been arrested after customs officers seized over nine million cigarettes at Belfast Docks.
In the first seizure, 3.5 million John Player Special-branded cigarettes were found on Tuesday night by officers from the UK Border Agency.
They were concealed in two containers under a cover load of granite.
On Wednesday morning, officers uncovered nearly six million mixed-brand cigarettes hidden under a load of peppers during a search of a 40ft trailer.
Both consignments of cigarettes are suspected counterfeit.
A spokesperson for Her Majesty's Revenue and Customs said the loss to the public purse would have been £2m.
John Whiting, from HMRC, said that tobacco smuggling is "not a victimless crime".
"The huge profits reaped from the sales of illegal cigarettes are ploughed straight back into the criminal underworld, feeding activities like drug dealing and fraud," he said.
"Purchasing cheap cigarettes without the duty paid on them means trading with criminals, and undermining honest businesses."
Maggie Eyden, of the UK Border Agency in Northern Ireland, said that the Border Agency and the HMRC were committed to stamping out the problem of cigarette smuggling.
"This criminal activity undermines public health by creating a cheap and unregulated supply. These criminals don't care who they sell their illicit goods to and are motivated purely by illegal profit to fund further crime."
© UTV News