* CEO Cucchiani clashing with key board member, investor-sources
* He could be ousted at board meetings on Tuesday-sources
* Bank dismisses talk of Monte Paschi rescue (Adds sources on showdown, details, bank's denial of Monte Paschi rescue)
By Paola Arosio and Gianluca Semeraro
MILAN, Sept 26 (Reuters) - Enrico Cucchiani, the CEO of Italy's No.1 retail bank Intesa Sanpaolo, could be forced out next week after clashing with supervisory board chairman Giovanni Bazoli and the bank's second-largest investor, sources close to the bank told Reuters.
Intesa's supervisory and management boards are due to meet on Tuesday for regular meetings.
Two sources close to Intesa said the two boards were likely to withdraw backing for Cucchiani, who was appointed in November 2011 after long-standing Chief Executive Corrado Passera quit to join the government of then-premier Mario Monti.
They said an attempt by supervisory board chairman Bazoli to oust Cucchiani was backed by Bazoli's ally Giuseppe Guzzetti, the powerful boss of Fondazione Cariplo, a charitable foundation that is also Intesa's No.2 shareholder.
"That there is a lot of unhappiness is a given. There are differences over strategy and management," said one of the two sources. "We can't pretend nothing is happening, Tuesday will be an important day."
However a third source close to the bank said the outcome of next week's board meetings was still open.
"The impression is that the bomb (management tensions) may have exploded a bit too early. A hasty solution may damage the bank," said the source.
A fourth source with direct knowledge of the situation said the future of the CEO was not on the agenda of the management board meeting, adding any decision to oust him would have to be taken by the supervisory board, led by Bazoli.
The bank declined to comment about the management struggle or about any possibility of Cucchiani being ousted.
Cucchiani, 63, was formerly at the helm of the Italian unit of German insurance giant Allianz. His pro-market approach has won praise within Intesa's management board and he is well respected internationally, one person with direct knowledge of the situation said.
However, several Intesa insiders told Reuters he clashed with 80-year-old Bazoli and Guzzetti over his solitary management style.
If Cucchiani is ousted, it would mark a break from the past for Intesa, which likes to portray itself as a prudent, conservative lender not inclined to sudden management shake-ups or boardroom showdowns. Cucchiani himself has often said the bank's appeal is that it is "boring".
"The bank is not used to violent outcomes," said one senior Italian banker who has worked at Intesa.
Bankers and insiders pointed to Carlo Messina, the bank's deputy director general, as a possible successor to Cucchiani.
Shares in Intesa fell on Thursday with traders citing market talk that the management clash focused on whether Intesa should help save smaller loss-making rival Monte dei Paschi di Siena - an option opposed by Cucchiani.
The head of Intesa's management board, Gian Maria Gros-Pietro, dismissed in a statement the talk of a tie-up between the two lenders, saying it was "completely groundless".
Cucchiani told Reuters in an interview earlier this month that Intesa would not join an expected wave of consolidation in the Italian banking industry.
A person who knows him well said Cucchiani is opposed to so-called systemic deals, whereby a bank such as Intesa would ride to the rescue of struggling companies to keep them in Italian hands.
Monte dei Paschi, which is at the centre of a derivatives scandal and took a state bailout earlier this year, needs to find investors willing to join a 2.5 billion euro capital hike to avoid being nationalised.
Intesa's shares closed down 3.8 percent, underperforming a 1.2 percent fall in the FTSE MIB blue-chip index amid fresh political tensions. (Additional reporting by Stefano Rebaudo, Valentina Za and Lisa Jucca; Writing by Silvia Aloisi; Editing by Lisa Jucca and Pravin Char)