The spokesman for the prosecutor’s office in the southwestern city of Baden-Baden said officials in Mannheim were “examining” UBS activities, while stressing that it did not mean they were opening a full investigation.

Journalists for the Frontal 21 program of the public broadcaster ZDF had passed themselves off as Germans who sought to place money abroad without attracting the attention of tax authorities.

Fitted with a hidden camera, they reportedly spoke with staff at a UBS branch in Baden-Baden and then with a bank officer in Switzerland. Images of the subjects’ faces were scrambled and their voices transformed.

The program showed what it said was the director of the German branch of UBS, initially saying he would handle “only legal money” but then suggesting several options “if you want more discreet methods.” He proposed setting up a trust in Liechtenstein or an investment in Singapore.

Another purported UBS employee quoted in the report added that necessary documents were to be handled by an internal UBS postal service but could also be transported by car “with German license plates to avoid raising suspicions among neighbours.”

“We are going to investigate the conversation recorded during the programme with regards to UBS,” UBS bank told AFP in a statement. It said the bank’s employees are expected to respect the law and clear internal regulations, adding that “the active aiding of tax evasion is neither permitted in Switzerland nor in Germany.”

The programme was aired following the disclosure last month of a vast German tax evasion scandal. An investigation has been launched of hundreds of Germans suspected of seeking to avoid paying taxes on money placed in Liechtenstein trusts.

The German government said it paid an informer for bank data that led to the biggest tax fraud probe ever in Germany and sparked similar investigations around the globe.

Austria, Australia, Britain, Canada, France, Greece, Italy, New Zealand, Spain, Sweden and the United States have launched investigations into their citizens’ investments in Liechtenstein.

Switzerland’s finance minister has criticized Germany’s handling of the affair and launched a fierce attack on foreign critics of Swiss banking secrecy laws.