By Giuseppe Fonte and Valentina Za

ROME, Dec 7 (Reuters) - France's Credit Agricole CAGR.PA had informal backing from the Italian government before it said on Friday it was raising its stake in Banco BPM BAMI.MI, two sources close to the matter told Reuters.

The increase intensifies a banking battle in Italy, begun when UniCredit CRDI.MI last month made a takeover offer for Banco BPM, scuppering the government's plan to help bring about a merger between BPM and state-backed Monte dei Paschi di Siena BMPS.MI.

Credit Agricole declined to comment.

Ruling out a full takeover bid, Credit Agricole said on Friday it had entered derivative contracts to raise its holding in BPM to 15.1% from 9.9%. It is seeking European Central Bank approval to buy up to 19.99%.

Asking not to be named due to the sensitivity of the matter, the sources said that, before acting, the French bank had informed and obtained an informal nod from Italian Prime Minister Giorgia Meloni's government.

Separately, a source familiar with Credit Agricole's strategy told Reuters the bank aims to strengthen its negotiating position to protect commercial agreements that generate revenues in its biggest market outside France.

Credit Agricole became Banco BPM's main investor in 2022, shortly after an earlier aborted takeover attempt of BPM by UniCredit.

Credit Agricole partners with BPM in consumer credit and insurance. Its asset management arm Amundi AMUN.PA has a distribution contract with UniCredit that runs out in 2027.

Present in Italy since 1972, Credit Agricole has grown steadily in the country, partly through small acquisitions. Officials in Rome have previously told Reuters it has always reassured the government about its strategy, ruling out any overly aggressive move to seize market share.

The strategy has not changed, one of the sources said.

Approval from the Italian government, as well as the European Central Bank, is necessary if Credit Agricole is to raise its stake in BPM.

The Italian government has "golden powers" that allow it to block or set conditions on foreign and domestic corporate takeovers in strategic sectors such as energy, telecoms and banking.

Under Italian rules, the cabinet office must approve share ownership in any Milan-listed strategic company when it crosses thresholds set at 3%, 5%, 10%, 15% and other intervals up to 50%.

UniCredit CEO Andrea Orcel has said his bank could not afford to be sidelined as Italian banking consolidation sped up. Banco BPM had moved to buy fund manager Anima Holding ANIM.MI and take a stake in Monte dei Paschi days before UniCredit launched its bid with a near zero premium.

($1 = 0.9463 euros)

(Reporting by Giuseppe Fonte in Rome and Valentina Za in Milan; Editing by Gavin Jones and Barbara Lewis)

((giuseppe.fonte@thomsonreuters.com; +390680307711;))