Searches were carried out at private and commercial premises in Belfast, Kilkeel, Newry and Lurgan on Tuesday.
Following these searches four of the men were detained, the fifth presented himself to the PSNI yesterday.
Almost 4,000 litres of fuel was seized during the operation along with two flatbed lorries and eight cars.
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Custom officers said the seizures followed several months of surveillance targeting the sale of laundered green diesel to commercial users across the Province.
In June, law enforcement agencies from both Northern Ireland and the Republic established a cross-border group to tackle fuel fraud.
The new multi-agency strategy involved members of the Gardaí, Revenue and customs officers, the Criminal Assets Bureau and their counterparts in Northern Ireland.
It is suggested that the Northern Ireland exchequer loses out on hundreds of millions of pounds because of fuel fraudsters, who pocket 50p for every litre of illicit fuel they sell on.
(PR)
