Italy's economy minister said on Monday he was surprised by the decision to give priority to Credit Suisse shareholders over bondholders after the Swiss bank said $17.2 billion of its Additional Tier 1 debt would be written down to zero as part of its rescue merger with UBS.

Speaking on the sidelines of an event in Milan, Italy's Economy Minister Giancarlo Giorgetti said however that the impact of the Credit Suisse crisis on the Italian banking system was "insignificant".

Some of the world's largest central banks came together on Sunday to try to stop a banking crisis from spreading as Swiss authorities persuaded UBS Group to buy rival Credit Suisse in a historic deal.

The Swiss regulator, said the decision to write down to zero the Additional Tier 1 bonds would bolster the bank's capital. ($1 = 0.9289 Swiss francs) (Reporting by Elvira Pollina, writing by Federico Maccioni, editing by Keith Weir)