A US tax programme that encourages UBS clients to avoid criminal inquiries by declaring offshore accounts before 23 September has triggered disclosures by clients of Credit Suisse, Julius Baer, LGT Group in Liechtenstein, HSBC, and Bank Leumi Le-Israel, the news agency said, quoting tax lawyers.

The report said the US Internal Revenue Service may, as a result of the disclosures, obtain ammunition to target other overseas wealth managers as it seeks to crack down on tax evasion.

UBS avoided prosecution in February of this year when it admitted helping US citizens evade taxes, paid a $780 million penalty, and disclosed secret data on 250 clients. In August, UBS agreed to reveal another 4,450 clients to settle a US lawsuit seeking more data.

The developments are seen as having landed a serious blow on Switzerland’s centuries-old tradition of banking secrecy. The tradition has been a key ingredient in driving Swiss banking, although the country has, in recent years, moved to adapt to an increasingly hostile environment for offshore tax regimes. About 13 per cent of Swiss GDP stems from its financial sector.

UBS has, in addition to the settlements in the US, ceased to provide offshore banking facilities for US citizens.

“It is very possible that the IRS will be able to get strangleholds over the other banks because they’ll have specific information which will permit them to bring specific allegations of wrongdoing before the US courts,” Robert Fink, an attorney at Kostelanetz & Fink in New York, was quoted as saying by the news service. “This thing may spread like wildfire,” he said.

Mr Fink, whose firm handled more than 250 disclosures, said his clients told the IRS about accounts at a dozen Swiss banks, as well as banks in Germany, England, Italy, Belgium, Singapore and Hong Kong.

Lawrence Horn, an attorney at Sills Cummis & Gross in Newark, New Jersey, said his clients declared accounts at Bank Hapoalim in Israel, as well as banks in the Bahamas, Granada and the Cayman Islands, the news agency added.