* Rising M&A expectations lift Italian banking stocks

* Orcel set to weigh alternative M&A options to MPS

* Banco BPM seen as a potential target

* Takeover threat could hasten merger talks with BPER

MILAN, Feb 12 (Reuters) - The arrival of star dealmaker Andrea Orcel at the helm of UniCredit risks complicating Rome's bid to clinch a rescue deal for problem bank Monte dei Paschi di Siena.

Generous tax incentives designed to pave the way for a sale of Monte dei Paschi (MPS) are seen spurring other Italian bank mergers in 2021, and UniCredit is weighing its options after rival Intesa Sanpaolo last year secured a fifth of the market with its UBI takeover.

But Orcel's search for the best match for UniCredit may be at odds with the Italian Treasury's push to cut its stake in MPS, which cost it 5.4 billion euros ($6.5 billion) in 2017. MPS now needs another 2.5 billion.

The Treasury expects incoming Prime Minister Mario Draghi, a former European Central Bank chief, to back plans to re-privatise MPS so it does not become a permanent drain on taxpayers, a person familiar with the matter said.

"Draghi has ... the credibility and authority to convince UniCredit investors a potential deal might be in their interest," said Andrea Resti, a professor at Milan's Bocconi University and an adviser to the European Parliament on banking supervision.

Resti said the "ingredients" for consolidation were all in place. "Discounted valuations for banks, though increasingly less so, tax incentives and cost cuts as pretty much the only profit lever."

But MPS is not the only game in town.

Banco BPM, with roots in Milan's wealthy Lombardy region, is also scouting for a partner.

A combined UniCredit and Banco BPM would have a market share of more than 20% in Italy's industrial north, rivalling Intesa's, JPMorgan analysts calculated.

Rome intends to rid MPS of any legal risks before selling it, but bankers say the Tuscan bank's troubled history favours Banco BPM, together with its 19.4% stake in asset manager Anima .

The state, on the other hand, is offering to take on at least 14 billion euros of UniCredit's impaired loans as part of an MPS deal and to cover a portion of its proposed cash call.

MPS would increase UniCredit's market share to around 17% in terms of branches, not far from the roughly 19% share UniCredit would secure by buying Banco BPM, JPMorgan said.

CLOCK TICKING

After Orcel was picked to be UniCredit CEO, he signalled in preliminary contacts with the Treasury that he favoured Banco BPM over MPS, a person briefed on the discussions said.

This person said Orcel had not ruled out a three-way deal if he could not get out of acquiring MPS.

UniCredit declined to comment on the matter. Orcel was not immediately available for comment.

A three-way deal would face significant execution risks but plenty of scope for cost cuts, with thousands of jobs at risk.

UniCredit and Banco BPM last year held preliminary merger talks but people with knowledge of the discussions said conditions for an agreed deal between the two were no longer in place, raising the prospect of a takeover bid by UniCredit.

After talks with UniCredit fell through, Banco BPM has been looking at a tie-up with rival BPER Banca and people close to the matter have told Reuters the two aimed to reach an deal in the first half of 2021.

BPER's M&A plans are driven by the ambitions of its top investor, insurer Unipol, which wants to secure a large distribution network for its products.

Orcel will not take up his job at UniCredit until mid-April, giving Banco BPM and BPER, respectively Italy's No.3 and No.5 banks, time to speed up talks, which a person close to the matter said had resumed after a pause.

On Friday, Unipol boss Carlo Cimbri said BPER needed time before engaging in M&A because it had to appoint a new board and integrate 600 newly acquired branches.

But the two banks may need to make a quick decision on a deal, which Exane-BNP Paribas analysts described as "the most attractive alternative for Banco BPM's management and ... the only transformational option available to BPER."

"There are many pieces that would need to quickly fall into place: valuations, roles, governance. It's tough, but the threat from Orcel's UniCredit is just what could make this possible," an Italian banker said.

($1 = 0.8263 euros) (Additional reporting by Pamela Barbaglia in London and Stephen Jewkes and Gianluca Semeraro in Milan; Editing by Jane Merriman)