(Reuters) -Star Entertainment on Monday confirmed it had received approaches for "potential transactions" from parties, including a group of investors consisting of Hard Rock Hotels and Casinos, as the troubled Australian firm tries to revamp operations.

Star's shares were up about 21%, as of 0407 GMT, while the benchmark index traded 0.7% higher.

The Australian Financial Review reported earlier in the day that a consortium led by Florida-based Hard Rock was considering taking control of Star.

After that, Star Entertainment said it had received "inbound interest from a number of external parties" but flagged none of them had yet resulted in "substantive discussions".

About a couple of hours later Star updated the market again, saying Hard Rock Hotels & Resorts (Pacific) was among a group of investors who are looking to buy the firm. It did not give other details.

Australian casino operators have been under the lens of regulators over the last few years with Star's major rival, Blackstone-owned Crown Resorts facing similar inquiries that exposed a slew of wrongdoing.

Star is currently undergoing a regulatory inquiry to keep its gaming license at the Sydney casino which makes the firm's future uncertain. The Sydney inquiry's final report is due July 31. It is also looking for a new chairman and a CEO after both resigned earlier this year.

"While the market has reacted positively to the speculation about an acquisition by Hard Rock, Star Entertainment Group's 73,000 shareholders will have a large say in the outcome of this," said Ben Williamson, co-founder and co-CEO at InvestorHub.

"Star will need to engage its entire base to ensure any takeover is successful."