Switzerland is on the brink of a deal to settle a dispute with the United States over Swiss banks accused of helping Americans evade tax.
"We hope that we will shortly be at the finishing line," finance minister Eveline Widmer-Schlumpf told Swiss radio in an interview said on Saturday. "The banks won't get it for nothing."
She declined to say how high fines might be, but added: "It is clear that it will not be a pleasant solution."
Bank secrecy is under fire since the financial crisis began, as governments seek to clamp down on tax evasion.
The Swiss government has been in protracted talks to end US investigations into Swiss banks, in return for heavy fines and a transfer of client names.
Credit Suisse has already made provision of 295 million Swiss franc ($US303 million) towards a settlement.
UBS, the country's biggest bank, was forced in 2009 to pay a fine of $US780 million and hand over the names of more than 4000 clients - information that allowed the United States to then pursue other Swiss banks.
Switzerland's oldest private bank, Wegelin & Co, said in January it was closing after pleading guilty and paying a fine of nearly $US58 million.
EU finance ministers gave official approval this week to start formal negotiations with Switzerland Liechtenstein, San Marino, Andorra and Monaco about surrendering bank data on an automatic basis, exposing savers to tax claims.
Ms Widmer-Schlumpf said Switzerland could do little to resist the pressure for more transparency.
"The automatic exchange of information can't be stopped," she said.