Customs officers and authorities from the North have seized more than 90,000 litres of fuel in a cross-border operation.
The operation last week saw the fuel seized in Counties Antrim, Armagh, Cavan, Donegal, Down and Louth.
In Cavan, Donegal and Louth Revenue Customs officers seized 29,000 litres of fuel with a potential loss of revenue amounting to almost €16,000, following checks on retail outlets.
Two UK-registered vehicles were also seized and Customs officers have questioned a number of people.
Officers from HM Revenue & Customs in Northern Ireland seized a total of 61,800 litres of fuel from retail outlets and one man was arrested. Six adapted vehicles, a number of tanks, pumps and fuel pods were also seized in the North.
“Cross border operations have recently been stepped up in response to the establishment, last year, of the Cross-Border Fuel Fraud Enforcement Group,” a spokesman said.