Switzerland must immediately settle its tax rows with countries such as France or its banks will lose many clients, the head of the Swiss Private Bankers Association (SPBA) said on Thursday.

"We need to quickly find a solution that will not push clients who have put their trust in Swiss banks to seek refuge in other countries," Nicolas Pictet told reporters in Bern.

Faced with mounting international criticism that its banking practises enable wide-scale tax evasion in other countries, Switzerland reached agreements last year with Britain, Austria and Germany to ease its cherished bank secrecy.

The accords with London and Vienna took effect on January 1, but the German parliament ended up blocking that country's deal last last year.

Under the agreements, foreigners that deposit undeclared funds in Switzerland maintain their anonymity but are taxed by Bern, which in turn transfers the revenues to the account holder's country of origin.

The central European country is also in the process of negotiating similar deals with Greece and Italy, but neighbouring France has so far refused to discuss any agreement on regularising undeclared French funds stashed in Swiss banks.

"We have not yet found a modus operandi," Pictet told AFP, stressing the urgent need to clarify the situation.

"For Swiss private banks, the quicker the better," he added.

While bilateral tax deals topped Switzerland's foreign relations agenda in 2012, Pictet stressed Thursday that Bern should now focus more on reaching deals with the EU on financial services.

"Due to the crisis, the countries that surround us are closing in on themselves," he said, pointing to a sharp rise in European directives in this area.

While acknowledging that the directives aim to protect investors and ensure smooth sailing for the markets, Pictet pointed out that they also often have unstated goals: "to raise barriers to block access to markets by outside operators."

If the situation was not quickly brought under control, Switzerland risked seeing its all-important financial services sector waste away, he cautioned.