PARIS, June 28 (Reuters) - French supermarket retailer Casino on Wednesday set a deadline of July 3 for offers to boost its equity base, as it works on a debt restructuring which it said would result in shareholders facing a large dilution on their holdings.

Casino has two rival 1.1 billion euros ($1.20 billion) bid proposals to boost its equity base.

One is from main shareholder Jean-Charles Naouri who has teamed up with French billionaire Xavier Niel and the other is from billionaires Daniel Kretinsky and Marc Ladreit de Lacharriere. Naouri chairs the Rallye holding company that currently controls Casino.

Casino said it had requested that those involved in these proceedings submit "new money equity offers" by July 3 at the latest. It also reaffirmed it needed an equity contribution of at least 900 million euros.

"Casino's vision of the debt amounts to be converted into equity will be discussed with the potential new money equity providers as well as with the group's financial creditors so that the final restructuring proposal may differ from such vision," the company said in a statement.

"In any event, the current shareholders of Casino will be massively diluted and Rallye will no longer control Casino," it added.

($1 = 0.9158 euros) (Reporting by Sudip Kar-Gupta Editing by Chris Reese and Sandra Maler)