A major disposal operator has been shut down after the discovery of hundreds of thousands of tons of waste buried illegally on land near Derry.
Northern Ireland environment minister Alex Attwood signed off an order following an investigation by his department's environmental crime unit which unearthed a sophisticated racket to conceal vast amounts of waste in the Mobouy area.
He said: "Material was mangled and shredded to hide its original sourcing, with illegal landfills being topfilled with soil and clay to deceive and hide illegal waste.
"The scale of this is clearly well organised - the scale of this means it involves organised crime."
The owner of the waste management facility closed down - which has not been identified - has now been given two months to transfer the material to a legal landfill site for disposal.
Owners of the land where waste was hidden have also been ordered to take action to prevent environmental damage by getting rid of polluting liquid.
The minister revealed he is setting up a special waste crime task force as part of new measures to crack down on criminals involved.
Chris Mills, a former chief executive of the Welsh Environment Agency, is undertaking an immediate review of the workings of the Department of the Environment's waste unit. Up to 25 sites where risk may exist are to be checked out and district councils have been told to tighten up on waste collection arrangements in a bid to thwart illegal dumping linked to fuel laundering.
Two people have been questioned as part of Operation Sycamore, and according to the department more arrests are expected.
But Upper Bann MP David Simpson said criminals running the multimillion-pound fraud were still avoiding prosecution - even though illegal plants had been dismantled.
He said the Government had talked about a new fuel marker for long enough, but it was now time for action. One plant discovered last month, he claimed, laundered 40,000 litres which would have cost the Exchequer £4.8 million in lost revenue.
In 2011 the UK's largest illegal plant, which had the ability to launder 30 million litres a year, was discovered in South Armagh.
Mr Simpson said: "It seems to me that the fuel launders are always one step in front of the Government and the officials in HMRC (HM Revenue and Customs). We've been hearing talk about a new fuel marker for years. Reports as early as 2002 were indicating that we needed a new fuel marker yet the launders seem to be still running rings around the authorities.
"HMRC can be very swift in tackling a business that is struggling to keep on top of its tax commitments yet the fuel smugglers are roaming all over the United Kingdom seemingly unhindered.
"Other than a few dawn raids every year which shut plants down for a period of time we rarely see the crime's masterminds being put out of business. They simply move their operation to another location.
"Government must make it a priority to get out in front of the criminals and make it more difficult for fuel to be laundered. This should include incentivising universities and young graduates to take up further research in this matter. It's time for HMRC to get out in front of the criminals."