Steve Wynn is suing Wynn Resorts and the Massachusetts Gaming Commission (MGC).
The former Wynn Resorts CEO, who resigned in February, is alleging the operator "improperly handed over privileged documents" for the MGC’s investigation into sexual misconduct claims against him.
According to reports, Wynn’s lawsuit seeks to prevent the MGC from releasing any investigative report if it contains privileged materials.
The lawsuit states: "Mass Gaming officials have conducted their months-long investigation into Wynn Resorts with total disregard for protecting the privileged communications of Mr Wynn.
"They have simply donned the judge’s robe, cracked the gavel, and unilaterally determined Mr Wynn has failed to sustain his burden of establishing that any privilege applies to the unknown universe of documents acquired during the Mass Gaming investigation."
In response, the MGC said the lawsuit is no surprise given Wynn’s "litigious tendencies."
Spokeswoman Elaine Driscoll added: "The commission has retained legal representation in Nevada to mount a vigorous defence against his effort to block the release of our months-long investigatory report and to defend against Mr Wynn’s baseless claims for damages."
Wynn Resorts yesterday reported a 10% year-on-year increase in operating revenue for Q3 to $1.71bn, which was largely down to performance in Macau, as Las Vegas figures declined.
However, warnings of a Macau "slowdown" after Golden Week have prompted Wynn Resorts’ share price to fall.