Germany has quietly dropped a proposal for a new pan-European truck toll from the agenda of its European Union presidency, prompting calls by environmental groups and truck makers Scania and Volvo for it to be reintroduced.

Plans for a so-called Eurovignette, which seeks to penalise polluting vehicles and spur the sale of cleaner trucks, have been dropped from the German agenda, Germany's Transport Ministry confirmed on Thursday.

Germany's decision follows concerns about additional costs in difficult economic times and removes an incentive for freight companies to upgrade to new, less polluting vehicles.

That potentially reduces sales and has prompted green activists and some truck makers to complain to Europe's Transport Ministers.

"The failure, under the German presidency, to put the Eurovignette on the agenda of the Council of Transport Ministers on September 28 is extremely worrying," environmental groups and the truck makers said in a joint letter to European Transport Ministers.

"The reform of the Eurovignette is a decisive instrument for investments by both manufacturers and freight forwarders, thus making the transition to low or zero emissions in transport possible," says the letter to the EU transport ministers.

In addition to Volvo and Scania, the environmental associations Natuur&Milieu, Transport and Environment and the European freight forwarders' association Clecat signed the letter, which was seen by Reuters.