* Enel expected to hold a board meeting on the deal on Saturday
* CDP set to take control of broadband infrastructure firm
* Deal seen as a potential boost for network project with TIM (Adds Open Fiber statement, details)
MILAN, April 30 (Reuters) - Cassa Depositi e Prestiti (CDP) said on Friday it had agreed to present an offer to Enel ENEI.MI for 10% of Open Fiber in a move that would raise the Italian state lender's stake in the broadband infrastructure firm to 60%.
The move comes as Enel, Italy's biggest utility, prepares to sell its stake in Open Fiber. Australian fund Macquarie MQG.AX has offered up to 2.65 billion euros ($3.20 billion) for all or part of Enel's 50% holding.
Enel is expected to hold a board meeting on Saturday to discuss the deal, three sources with knowledge of the matter said. Open Fiber on Friday said it gave the required go ahead to the entrance of Macquarie in its capital.
CDP also said it had approved a binding term sheet with Macquarie outlining governance of Open Fiber ahead of the fund becoming a shareholder in the fibre-optic business.
With a controlling stake in Open Fiber, CDP could potentially ease a long-mooted plan to merge Open Fiber network assets with those of Italy's former phone monopoly Telecom Italia TLIT.MI to create a unified network operator.
Bets on the single broadband network project following CDP's announcement lifted shares in Telecom Italia by as much as 4%, making it the biggest gainer on Milan's blue-chip index .FTMIB . is the second-biggest shareholder in Telecom Italia, behind French media company Vivendi VIV.PA .
A single network would avoid duplicating investments in fiber rollout as Italy works to close its digital divide with the rest of Europe, a priority of the previous government of Prime Minister Giuseppe Conte.
However, some ministers of the new government led by Mario Draghi have cast doubts on the plan due to regulatory issues, saying alternatives options are also being considered. said it was committed to bringing in "new resources" before the closing of the deal to help speed up broadband network development.
Under a proposed scheme, CDP and Enel will each inject cash into Open Fiber to boost its finances, the three sources told Reuters. One source said each partner was likely to put in around 150 million euros.
State-controlled Enel declined to comment and added it would make a statement only after analysing official documents.
($1 = 0.8278 euros)