German Chancellor Angela Merkel's Christian Democrats (CDU) and their Bavarian coalition partner have clashed in an unusually public spat over plans to introduce a motorway toll that critics say is designed to fleece foreigners.
Bavaria's Christian Social Union (CSU) want foreign motorists to pay tolls on German motorways and other roads. They say it is unfair that foreigners travel for free on German motorways while Germans have to pay tolls in neighbouring countries such as Austria, Switzerland and France.
Senior CDU members, Armin Laschet and Thomas Strobl, said the introduction of tolls on all roads and motorways would impose an excessive burden on motorists and cause more problems than they would solve for Germany's regions.
Their criticism drew an angry response from CSU deputy leader Andreas Scheuer in Monday's Sueddeutsche Zeitung daily.
"That just shows how completely clueless they are," he said, in a surprisingly sharp rebuke of the centre-right CDU that exposed the split in Germany's conservative camp on the eve of elections in three German regions that start on Sunday.
"The toll is going to be introduced on all roads in Germany," Scheuer said, whose conservative party agrees with the CDU on most other issues.
Opinion polls show Germans favour a road toll for foreigners. The issue is especially sensitive in Bavaria, a major crossroads for foreign motorists travelling from northern European countries to the Balkans and southern Europe.
The motorway toll issue has dominated German media for months, vying with major international crises such as Ukraine, Syria and Gaza for public attention.
The CSU pressed the motorway toll issue in coalition talks after last year's German federal elections.
But Merkel's CDU and its other coalition ally, the centre-left Social Democrats (SPD), said they would only back the toll if it did not lead to extra costs for German motorists and if it complied with European Union rules that prohibit discrimination against foreign motorists.
German Transport Minister Alexander Dobrindt, a CSU leader, has proposed a compromise whereby annual taxes now paid by all German motorists would be lowered by about the same €88 fee the envisaged annual motorway toll would cost.
German parliament experts have said the plan might still violate EU rules.
Dobrindt has said the planned toll could generate an additional €2.5 billion in annual revenues for the budget.
"Foreign drivers don't pay anything at all to use German roads while we've got to pay to use roads abroad," said Ilse Aigner, Bavaria's state economy minister, on Monday.
Merkel, who long opposed the toll and reluctantly agreed to back it provided her conditions are met, said in an interview with ARD television on Sunday she expected "a lively discussion" on the issue in the months ahead and said the Dobrindt plan was now under study in Brussels to see if it conformed to EU rules.
"And after that we'll keep on talking about it," she said.