Officers have seized more than 80,000 litres of suspected illicit fuel following a three-day operation.
HM Revenue and Customs officers (HMRC) temporarily closed four petrol stations in Leeds, Motherwell, Cowdenbeath, Fife, and the Hillington area of Glasgow.
The petrol stations were closed between Friday and Sunday last week after the discovery of about 73,000 litres of fuel, thought to be illegal.
Two vehicles were also seized in Loanhead, Midlothian, along with a further 7,000 litres of suspected illicit fuel.
The estimated duty loss of all the seized fuel is about £56,000.
A 30-year-old man from the Crossmaglen, Northern Ireland, was arrested in Leeds and brought to Scotland to be interviewed but has been released pending further investigation.
Joe Hendry, assistant director for fraud investigation service at HMRC, said: “Fuel laundering is unregulated and dangerous.
“Illicit fuel is sold at reduced prices and motorists may think they are getting a good deal because it is cheaper.
“I would caution them to think again as the true cost is far from a bargain.”
The seizures and arrests follow a suspected fuel laundering plant in Northern Ireland being dismantled last week by HMRC officers.
Two men were arrested and the plant is thought to have the potential to produce more than 10 million litres of illicit fuel every year.
By Arthur Vundla