A German packaging regulation, covering imported bottled natural mineral water, is being challenged in the European Court of Justice by the European Commission.

The German regulation of 1998 imposes a re-use scheme on importers, obliging them to ship empty packaging back to the country of origin. When bottled mineral water is brought in over long distances this can mean a heavy cost burden for importers.

Brussels says that the regulation is discriminatory and thus violates the EU's free trade rules.

EU Environment Commissioner Margot Wallström said the German rules did not take proper account of the environmental costs of sending containers of natural mineral waters over long distances for re-use.

"They are a barrier to trade without environmental justification, and I urge the German authorities to change them in an environmentally appropriate way," she said.

The legal action follows the failure of the German authorities to change the 1998 law in spite of promises to do so.