The tiny alpine principality, which lies between Switzerland and Austria, intends to introduce new clauses into an agreement it made in March with the German government, daily Süddeutsche Zeitung reported.
The changes mean it would give no help to countries such as Germany in investigating tax evasion if a case involved stolen bank data.
Data theft has become a contentious issue after Germany launched tax investigations over untaxed money held in both Liechtenstein and neighbouring Switzerland.
Liechtenstein recently made an agreement with 11 countries, including Germany, that obliges the principality to follow an OECD guideline whereby countries work together to prosecute tax dodgers in cases where there are strong grounds for suspicion.
A government spokesman in the Liechtenstein capital Vaduz confirmed that the principality would not provide legal help if an investigation was grounded on stolen data.
The clause was following the wishes of Switzerland, the spokesman said. Switzerland was outraged earlier this year when German authorities paid a reported €2.5 million for data stolen from a Swiss bank.
The German government has raised about €200 million in back taxes from secret accounts in Liechtenstein since it bought stolen bank data in 2008.
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The disk of data was purchased from a former employee of the Liechtenstein princely house's bank, LGT Group, and led to 588 investigations into tax violations, of which about a third have been completed, the government announced recently.