Monte dei Paschi di Siena is seeking a financial investor as the political storm over a derivatives scandal at the ailing bank intensified ahead of next month's Italian election.

Italy's third-biggest lender, which needs state loans to stay afloat, last week revealed opaque derivatives trades, conducted between 2006 and 2009, that could cost it some €720m.

The scandal has turned the spotlight on Monte Paschi's political ties with the centre left and on possible oversight failings by the Bank of Italy, then led by current ECB chief Mario Draghi.

"I would like to have a long-term financial investor," Monte Paschi Chairman Alessandro Profumo told Italian business daily Il Sole 24 Ore on Sunday. "Nationality is not a problem. The important thing is that it believes in our project".

Profumo was appointed head of a new management team last year to try to turn around the world's oldest bank.

At the root of Monte Paschi's problems is the acquisition in 2007 of smaller rival Antonveneta for a massive €9 billion in cash, stretching its finances to the limit just months before the global financial crisis hit.

Prosecutors are investigating why the bank paid such an inflated price for Antonveneta shortly after Spain's Santander had purchased it from ABN Amro for just €6.6 billion.

After an all-day board meeting on Saturday, the Bank of Italy gave approval to Monte Paschi's request for €3.9 billion of state loans, to be issued by the end of February, though one leading politician said they should now be blocked.

The Tuscan bank was forced to seek state aid last year for the second time since 2009 after becoming one of just four European lenders that failed to meet tougher capital requirements set by regulators.

Under the loan scheme Monte Paschi will issue €3.9 billion of bonds to the Treasury, with just under half of these replacing €1.9 billion of loans made under a previous plan.

Profumo has rejected suggestions the bank will be nationalised and said he was confident it would be able to pay back the loans and interest in cash over the next five years. "We believe in this. The objective is to return to profits already during the course of this year," he said.

However the scandal surrounding Monte Paschi is dominating the Italian media and has shot to the head of the campaign for the February 24-25 election.

Corriere della Sera daily on Sunday published excerpts from the minutes of Monte Paschi meetings in 2011 showing several board members expressing concern about the bank's portfolio, overladen with long-term Italian government bonds.

"The situation is no longer sustainable, we must take steps to reduce these positions," former vice chairman Francesco Caltagirone in September 2011 had said as Italian government bond yields soared during the apex of the euro zone debt crisis.

Monte Paschi's new management have said the main loss-making derivatives it uncovered involved Japanese bank Nomura and Deutsche Bank.