ROME The European Central Bank (ECB) is preparing to send a letter to Italy raising objections about the government's windfall tax on banks' profits, the Corriere della Sera daily wrote on Friday.

The letter will criticize the fact Rome announced the tax last week without previously informing either the Bank of Italy or the ECB as it is supposed to do under EU rules, the newspaper wrote, without citing sources.

The tax risks weakening Italy's banks and its economy in general, the ECB will say in the letter to be sent within "a couple of weeks" at the latest, the article said.

(Reporting by Stefano Bernabei, writing by Federica Urso, editing by Gavin Jones)