(Reuters) -Florida-based Hard Rock International has denied any involvement in a takeover bid for Star Entertainment, sending the troubled Australian casino operator's shares plunging on Tuesday.

Star on Monday said it had received interest from a group of investors which includes Hard Rock Hotels & Resorts (Pacific), pushing its shares up 20%.

Shares of the cash-strapped firm plunged more than 10% on Tuesday as investors expressed their confusion over the proposed takeover offer.

"We want to make it clear that Hard Rock International is not involved in, nor has it authorized, any discussions, activities or negotiations on its behalf in connection with a proposed bid for Star," the owner of The Mirage in Las Vegas said on Monday.

Hard Rock said it was investigating the matter and might take legal action to protect its brand and reputation.

Meanwhile, Star clarified it had not received any direct offer from Hard Rock International.

It had earlier said that Hard Rock Hotels & Resorts (Pacific) was a local partner of U.S.-based Hard Rock.

More details about Hard Rock Hotels & Resorts (Pacific) were not available.

(Reporting by Rishav Chatterjee in Bengaluru; Editing by Mrigank Dhaniwala)