The public debate over a bail-out of Opel is hurting its business, analysts warned on Monday, just as the German economy minister began a US mission to help the ailing carmaker.

Tim Urquhart, analyst at IHS Global Insight, said that sales of Opel and its British Vauxhall brand dropped by 21.9 per cent on a yearly basis in February, more than the European market average of 18 per cent.