ZURICH: Switzerland has vowed to prevent UBS from handing over client information to US authorities, in an attempt to defend bank secrecy, saying a tax case targeting its main bank is souring diplomatic ties.

Wealth management giant UBS is facing a court hearing in Miami next week after refusing to disclose data on 52,000 Americans holders of secret Swiss bank accounts to US tax authorities.

The Swiss Justice Ministry said yesterday that Swiss law prevents UBS from handing over client information and the government would seize UBS client data, if necessary, to stop that happening.