MILAN, Sept 28 (Reuters) - Mediobanca's top investor Leonardo Del Vecchio said on Tuesday it would propose changing the Italian merchant bank's by-laws to give more power to its board and investors.

The Italian billionaire, who owns 18.9% of Mediobanca through his holding company Delfin, said he had no plans to push to replace the bank's current board or management.

The proposed changes, however, aim to ensure Mediobanca's managers and directors pursue "the creation of value for all shareholders ... and ultimately leave the right to directors and shareholders ... to decide who should run the bank." (Reporting by Elisa Anzolin; editing by Valentina Za)