FLORENCE, Italy (Reuters) - The head of Italy's banking association ABI on Wednesday called for the European Central Bank to be the sole decision-maker over transactions in the industry, saying interfering with its independence to block one deal would be a mistake.

Comments by ABI President Antonio Patuelli come as UniCredit faces stark opposition in Germany to a potential offer for rival Commerzbank, in which Italy's No.2 bank has built a near 21% stake, conditional on ECB approval.

"If anyone interfered it would call into question not a single transaction, but the legitimacy of the banking union of which the ECB and its independence are the core," he told a press seminar.