The German government has paid an informant around €4.2 million ($6.17 million) for a CD containing Liechtenstein bank data on over 1,000 tax evasion suspects.

The information led to a full scale investigation into tax evasion which is expected to reap several hundred million euros, said a Finance Ministry spokesman.

Opposition politicians called for a swift clarification of the role played by the BND, Germay's intelligence service.

"It must be clarified whether the (intelligence) service operated within the framework of the permitted exchange of information between government officials," Max Stadler, a member of the opposition Free Democrats, told Tagesspiegel newspaper.

The tax investigation has already led to a raid on the home of Deutsche Post chief executive Klaus Zumwinkel. Mr Zumwinkel has come under pressure to resign after prosecutors said they suspected him of dodging about €1 million in taxes by transferring money to tax haven Liechtenstein.

Finance Minister Steinbrueck told reporters on Friday that Mr Zumwinkel had admitted evading taxes.

And, according to Reuters, police are likely to visit to hundreds more rich and prominent Germans as part of the probe into offshore accounts.

Liechtenstein Prime Minister Otmar Hasler is due to meet German Chancellor Angela Merkel and her finance minister, Peer Steinbrueck, on Wednesday in Berlin for talks on the missing millions.

Liechtenstein's LGT bank group, the wealth and asset management group of the Princely House of Liechtenstein, announced that it appeared the German authorities seemed to be working from a list of its clients stolen in 2002.

LGT spokesman Hans-Martin Uehlinger said the list would contain "several hundred names," adding, "we are going to warn all our clients who are on this list."

The bank said that "sensitive documents" had been stolen in 2002 by an employee of its subsidiary LGT-Treuhand, who had been tried the following year.

The bank thought that all the material had been returned but realised in 2007 that client data might have been "passed on illegally to third parties."

Der Spiegel magazine reported that the informant contacted the BND early in 2006. Several meetings with tax investigators followed that year during which the whistle-blower provided sample data to demonstrate the quality of the information.

Investigators subsequently paid for the information in full.