The issue has been raised to the top of the agenda as a huge tax evasion scandal, potentially involving hundreds of Germany's wealthiest citizens, and centring on the use of foundations registered in Liechtenstein, continues to unfold.

"There are some things, which I will talk about with Liechtenstein, which still remain to be done," Merkel was quoted as commenting by Reuters.

"It's not that nothing has happened in the past few years as to what concerns growing transparency. That gives me hope that we'll manage to solve the remaining ones in a clearer way," she added.

The scandal first broke last week after it emerged that the home of Klaus Zumwinkel, Chief Executive of Deutsche Post, one of Germany's largest companies, had been raided by police as part of a tax evasion investigation. He has been accused of hiding about EUR1 million from German tax collectors in Liechtenstein.

Zumwinkel was subsequently forced to resign by Deutsche Post, but the affair did not end there. On Monday, it was reported that several more homes and offices in the Frankfurt area and in southern Germany have been raided, after the intelligence services received information from a former employee of a Liechtenstein bank about hundreds of wealthy German clients.

The informant, an ex-employee of LGT, Liechtenstein's largest bank, is said to have handed over a disc to the German intelligence service, the BND, containing confidential information on more than 1,000 clients. The BND is believed to have paid the informant a sum of between EUR4 and EUR5 million for the disk - a sum which the German government is regarding as a sound investment, considering the potential payoff if the tax evasion allegations are confirmed.

In a statement released over the weekend, LGT Group, confirmed that "there are indications that client data stolen from LGT Treuhand AG in Vaduz has been unlawfully disclosed".

The statement revealed that confidential client data was stolen from LGT Treuhand AG in Vaduz by an employee in 2002. LGT Treuhand AG is a subsidiary of LGT Group, independent of LGT Bank, which is responsible among other things for setting up foundations.

The theft of the data was registered as a criminal offence and a court sentence was passed in 2003, with the sensitive material supposedly returned in full. However, in the summer of 2007, LGT became aware of "isolated indications" that client data had been illegally disclosed, and initiated an internal investigation to determine the source.

"Over the last few days signs have become clearer that this involves parts of the data stolen in 2002," the statement noted, adding that the scope of the presumed disclosure of the data "has not yet been established".

"LGT will immediately register a criminal offence against a person unknown and will do everything in its power to protect the interests of its clients," the statement added.

The statement stressed however, that the connection between the data stolen in 2002 and the reports of tax evasion by wealthy Germans "cannot be conclusively substantiated or confirmed".

The stolen data contains information about the client relationships of LGT Treuhand AG in Vaduz which were established prior to 2003. According to LGT, clients who have a business relationship only with LGT Bank (and not with LGT Treuhand AG), as well as all client relationships established from 2003 onwards with companies of LGT Group, are not affected by the theft.