Germany's proposed new motorway toll on trucks has put two leading European Commissioners on a collision course.

Transport Commissioner Ms Loyola de Palacio has ordered the proposed toll of up to 15 cents per kilometre and a toll rebate for truckers who refuel in Germany to be put on hold until the Commission investigates the plans.

Yesterday, German Commissioner for EU Enlargement, Mr Günther Verheugen, contradicted his colleague and said Berlin can proceed with the toll plan.

"Germany is completely free to introduce the toll as planned," said Mr Verhuegen to the Süddeutsche Zeitung yesterday. "The investigation concerns itself only with aspects of the financial assistance and also here just on a part of the intended aid: the reimbursement of petrol bills from German petrol stations."

A Commission spokesman declined to comment directly on Mr Verheugen's remarks.

"Ms De Palacio explained the Commission's position - the entire system will be examined," said the spokesman of the investigation launched two weeks ago. He said Ms De Palacio's office was studying a letter received last week from the German Transport Ministry on the planned toll.

Ms Michaele Schreyer, the EU Budget Commissioner, weighed into the row yesterday, criticising Ms de Palacio's approach to the dispute. "There is no legal basis whatsoever that could prevent the introduction of the toll," said Ms Schreyer to Berlin's Tagesspiegel newspaper, adding that she had sent a joint letter with Mr Verheugen to that effect to Commission President Mr Romano Prodi.

The Irish Road Haulage Association has said the the new system, making €600 million in rebates available to those who buy petrol in Germany, unfairly favours German trucking companies.

Berlin says the system will rebalance the scales for German truckers, who pay more for petrol because of higher fuel taxes in Germany and who were at a disadvantage to competitors who buy cheaper fuel in neighbouring countries.

The highly controversial toll was expected to be introduced at the start of this year, but technical and logistical problems pushed the date back to the end of this month, and now to the start of November.

A confidential report seen by Der Spiegel news magazine listed dozens of problems with the satellite-controlled toll system. Software was incompatible or non-functioning, distribution of dashboard trackers to calculate tolls is behind schedule and just 53 of 3,500 pay stations are ready.