Image caption Neighbours Germany and Switzerland have been involved in a spat over tax since 2010

Germany's upper house of parliament has rejected a deal with Switzerland to tax German assets held in Swiss bank accounts.

The deal would have allowed Germans with undeclared assets in Switzerland to avoid punishment by making a one-off payment of between 21% and 41% of the value of their assets.

The deal had been negotiated in April and was due to take effect in January.

But it needed to be ratified by both parliaments.

The rejection by the German upper house, the Bundesrat, prolongs the dispute between the two countries over how to deal with the estimated 180-200bn euros (£145-160bn) of German assets hidden in Switzerland.

German Finance Minister Wolfgang Schaeuble had called for support for the deal, saying: "The agreement tries to find a better solution for a situation which is unsatisfactory."

But Norbert Walter-Borjans, of the main opposition Social Democrats, told the Bundesrat it was a deal which made "honest taxpayers feel like fools".

Swiss Finance Minister Eveline Widmer-Schlumpf said her government remained "committed to a successful ratification".

And the Swiss Bankers Association said in a statement: "The German upper house has missed a major opportunity to reach a fair, optimum and sustainable solution for all parties to definitively settle the bilateral tax issues."