Netherlands defends border control project

If they spot a number plate which is red-flagged in the police database, officers will intercept the vehicle in a bid to stop illegal immigrants and criminals.

The cameras will operate in a zone up to 20km from the border and will initially look at small samples of cars and trucks for a maximum of six hours a day or 90 hours a month.

Dutch interior minister Gerd Leers said in a written statement in December the system "falls within the existing rules for border control and privacy."

He added: "The cameras will not constitute a permanent border. They only support the work of the Royal Military Police ... Since limitations [on travel] have been lifted in the European Schengen area, the surveillance system does not have the character of the former border."

The scheme has attracted criticism in German media.

Frank Richter, the head of the German police union, the GdP, told the German press agency the system puts "all travellers under general suspicion." Socialist politician Angelica Schwall-Duren said she has asked The Hague for clarification on how the number plate data will be stored.

For his part, Leers added that the European Commission has also quietly made enquiries and that he will file a report to Brussels.

The Dutch move comes after Denmark recently imposed and then lifted similar border checks.

The Netherlands in December also vetoed letting Bulgaria and Romania join the Schengen area despite the fact they met technical requirements. Polish interior minister Jerzy Miller at the time commented: "Mutual trust means keeping promises as well. Today that promise has been broken ... We live in difficult times for the EU."

Denmark and the Netherlands have influential far-right parties on their political scenes. But the anti-Schengen trend is bigger than the two northern neighbours.

French President Nicolas Sarkozy in a 'state-of-the-union' speech in December also said "Europe, which has to apply internally the principle of free movement but which does not control its external frontiers - that can't go on. Schengen must be reconsidered."

The statement alarmed Swedish foreign minister Carl Bildt who tweeted that Sarkozy is trying to win right-wing votes at the cost of EU values. "Election campaigns are what they are, but we must not endangered the gains we have made in creating a more open Europe," he said.