MFE, controlled by the family of the late former Italian Prime Minister Silvio Berlusconi, wants to spin off ProSieben's e-commerce and dating assets from the company's core TV operations.

The plan could help MFE mount a potential buyout approach for ProSieben's TV business, which MFE sees as crucial for its ambitions to build a pan-European broadcaster.

"In the opinion of the executive board and the supervisory board, a split-up ... lies in the unique interest of MFE, but not in the best interests of all other shareholders," ProSieben said in a statement.

The split would result in a significant increase in the financial leverage of ProSiebenSat.1 "and thus make strategic acquisitions just as impossible as a customary dividend policy", it added.

ProSieben's AGM is scheduled for April 30. The proposed spin-off needs a 75% majority to pass.

MFE already operates commercial TV businesses in Italy and Spain. It holds a nearly 30% stake in ProSieben.

The Milan-listed media company sees cross-border deals as a way to tackle the growing dominance of U.S. streaming giants such as Netflix and the flight of advertising investment to the likes of Facebook and Google.

ProSieben has, however, resisted MFE's calls to join the project and sought to develop a standalone strategy, with management pursuing the sale of certain investments in the Commerce & Ventures and Dating & Video segments in a bid to reduce debt.

Both boards "plan to focus clearly on the value-maximizing sale of the relevant investments over the next 12 to 18 months, subject to the market conditions", ProSieben said.

(Reporting by Klaus Lauer, Writing by Rachel More; Editing by Madeline Chambers, Miranda Murray and Kim Coghill)

By Klaus Lauer and Rachel More