State Secretary for Foreign Affairs, Michael Ambühl, made the comments during a trip to the US. He also used the occasion to make contact with the teams of the two presidential candidates, Barack Obama and John McCain.

The US authorities are currently investigating alleged income tax evasion by wealthy US citizens linked to UBS.

Earlier this month, a court order was won requiring UBS to produce details of its services to US clients from 2000 to 2007. This has raised questions over whether this could threaten Switzerland's traditional banking secrecy.

"I have reaffirmed the offer of the Swiss government to cooperate with US authorities under the existing legal bases," Mr Ambühl was quoted by Swissinfo as saying after talks in Washington with his US counterpart, William Burns.

"We expect that, in order to receive information from Switzerland, no unilateral measures will be taken against UBS so long as there is cooperation," said Mr Ambühl.

The probe has been aided by information from a former UBS employee, Bradley Birkenfeld, who admitted during a separate criminal case in the US to assisting tax evasion while at the bank.

UBS has said that it takes the matter "very seriously" was "working diligently with both Swiss and US government authorities, consistent with Swiss law and the legal frameworks for intergovernmental cooperation and assistance". But it has not yet explicitly said it will comply with the court order.

The Swiss finance ministry has reportedly not yet received any formal request for judicial cooperation from the US over the affair.