It has sent a legal final warning letter, a 'reasoned opinion', to the Dutch government, warning that it could ask the European Court of Justice to order the tests be scrapped, if the Netherlands refuses to abolish them first.
Brussels considers the tests to be unfair, because they are not required on vehicles previously registered in the Netherlands with another owner, when ownership is transferred. In a statement, the Commission said: 'These additional inspections prior to registration make the marketing of vehicles and trailers previously registered in another Member State less attractive, and therefore impede the free movement of goods.
'Such further inspections give rise to additional expense. Moreover, there is a waiting time of several weeks before the inspection is carried out.'
The Netherlands has two months in which to say how it will deal with the problem, or could face a court referral.