Italy has done too little in the last three years to reduce non-performing loans weighing on its banks, the European Central Bank's top bank supervisor told Italian daily la Repubblica today.

Daniele Nouy, who has headed the ECB's supervisory arm since it started overseeing the euro zone's top banks in 2014, welcomed a move by the Italian government to put aside €20 billion to support its weak lenders.

Nouy also rejected criticism that ECB adopted a softer treatment for German banks and declined to comment on a possible tie-up between Italy's biggest retail bank Intesa Sanpaolo and insurers Assicurazioni Generali.

"We do not comment on single banks ... we monitor developments very closely when they affect the banks we supervise and we keep in close contact with the other relevant authorities, where appropriate," Nouy saw quoted as saying by la Repubblica.