BERN (AFP) - UBS and other Swiss banks could be hit by more tax evasion lawsuits if a landmark settlement between UBS and the United States falls through, Switzerlands banking regulator warned Tuesday. Should no agreement be reached, there is a risk of further proceedings being instigated against not only UBS but other financial institutions as well, said Urs Zulauf, deputy head of the Swiss Financial Market Supervisory Authority. Ultimately, the risk of new proceedings will persist until a solution can be agreed that regulates the circumstances of all existing offshore relationships between US clients and Swiss financial institutions. UBS, the US and Swiss governments last August reached an agreement that requires the bank to reveal the identities of 4,450 American account holders suspected of having evaded US taxes. In return, US authorities were prepared to drop their lawsuit against the bank. However, the Swiss federal administrative court in January upheld an appeal by an American client of UBS against the transfer of banking details to the US authorities, effectively blocking the August deal. The court ruled that the 2009 agreement between the US and Swiss governments could not overwrite rules set out in an existing Swiss-US dual taxation agreement. The government is therefore seeking parliamentary approval of the accord so that it would stand up in court with a status equivalent to a treaty. Highlighting the importance of the case, Zulauf noted that Swiss finance has a deep-seated interest in finding long-term solutions to avert the growing threat of part of the financial centres current business model becoming criminalised under foreign law. Zulauf added that the issue was not just about UBS, nor is it just about the USA. Rather, it is about securing the long-term future of the entire financial centre. Switzerland has come under intense pressure in the past year over its banking secrecy rules, which critics claim are designed to protect tax dodgers. Bern has since negotiated several pacts with individual countries to offer more help in rooting out tax evaders.