Private investment bank Bankhaus Metzler and private bank Hauck & Aufhaeuser both had premises searched, the companies said.
Peer Steinbrueck, Germany's finance minister, said he would discuss financial transparency with Otmar Hasler, Liechtenstein's prime minister, when he visits Berlin this week.
He said: "I will be evaluating very carefully whether we need further initiatives at a European level to break up tax havens."
Angela Merkel, Germany's chancellor, has said Liechtenstein had advanced on transparency issues but some questions remained to be resolved.
Steinbrueck said he would discuss with Hasler how cooperation with the European Union on the matter could be improved.
Money for data
Meanwhile, Germany's finance ministry has said Berlin paid for information that led to the probe.
Acording to media reports, Germany's federal intelligence service gave an informant about $6.14m for a compact disk containing Liechtenstein bank data on more than 1,000 tax-evasion suspects.
Liechtensteinische Landesbank said last week it had been blackmailed for years by someone threatening to sell client data.
The bank's shares had fallen 12.42 per cent by Monday afternoon.
Asked whether it was right to pay a potential criminal to obtain information, Merkel said: "We must not mix up cause and effect.
"The fact that tax evasion was committed is a fact that is regrettable and must be clarified and followed up ... Parliamentary bodies will be informed about the way the information was obtained."