It follows three "reports of suspicious transactions" transmitted in recent months by the Bank of Italy financial information unit to the Guardia di Finanza -- the Italian police force that deals with financial crimes -- Gazzetta dello Sport newspaper reported.

Milan deputy prosecutor Fabio De Pasquale, in charge of 'International Affairs-Transnational Financial Crimes', has opened a specific type of file that is without either criminal offence or suspects. The file contains information relating to last year's sale as reported to the Guardia di Finanza.

Milan were sold in April last year by former Italian prime minister Silvio Berlusconi to a Chinese-led consortium for 740 million euros ($913m) with the use of offshore funds.

Since then, there have been questions about the financial stability of the consortium that subsequently went on a 200-million-euro summer spending spree on new players.

The seven-time European champions have taken a massive loan to manage repayments and are in trouble with European football's governing body UEFA over Financial Fair Play restrictions.

Should they qualify for European competition at the end of the season, they could be barred from taking part.Bank of America Merrill Lynch

(BAML) has been given the mandate to refinance Milan's debts.

American fund Elliott are reported to be ready to provide another 30 to 40 million-euro lifeline to ensure the club does not fall foul of UEFA, who will assess the club's finances in the coming months.

Li, 48, insisted last month that "the situation concerning my assets is safe and sound and that both the club and my companies are steadily working".

Italian prosecutors in January denied reports that they had opened an investigation into whether last year's sale was inflated for money-laundering purposes.

"As it stands no criminal proceedings have been opened regarding the sale of AC Milan," Francesco Greco, the chief prosecutor of the city of Milan, said on January 13.