The European Union has called on Switzerland to apply the same rules on tax issues as it did earlier this month with the United States.
EU Foreign Affairs Commissioner Benita Ferrero-Waldner said Brussels expected Switzerland to ensure that banking secrecy did not protect any form of tax scam.
She was speaking after talks in the Belgian capital with Swiss Foreign Minister Micheline Calmy-Rey.
Last week Switzerland gave Washington details of up to 300 clients of the country's largest bank, UBS, in what has been considered as violation of banking secrecy.
Swiss law distinguishes between tax evasion, a civil offence, and tax fraud. Banking secrecy is only lifted in cases of fraud.
Ferrero-Waldner also asked non EU-member Switzerland for further concessions in a row over preferential taxes for holding companies from the 27-nation bloc.
Calmy-Rey said dialogue on fiscal matters with Brussels would continue.
Thursday's meeting also covered plans for a framework agreement aimed at facilitating the implementation of a series of bilateral treaties between the two sides.