The new Her Majesty's Revenue and Customs (HMRC) regulations will come into effect on April 1.
Vehicles losing out will be mainly road-marking vehicles, road sweepers and crash barrier repair vehicles.
"This is because they are either not used in any way connected with surfacing a road, or else have a maximum speed exceeding 20kph," the spokesman said.
Under the new HMRC category of "road surfacing vehicle", vehicles designed only to perform an operation necessary to construct or restore a road, or the surface of a road will qualify.
The vehicles must not carry any load on a public road except what is necessary to propel it, or to operate any machinery built in, or permanently attached to, the vehicle.
But there will be a new category for tar sprayers. A vehicle to qualify for this must be designed and permanently built for the purpose – and unable to carry any load other than its own tar.
Director of CECA (North-East), Douglas Kell, which recently sought clarifications from HMRC, says: "Firms often used the cheaper red fuel rather than white in the past where permissible.
"Anyone not complying with the new regulation could risk prosecution and a fine. Since the alternative white diesel fuel costs around 50p a litre more than the red the additional tax raised will not be tiny. Contractors' costs are sure to rise."