Las Vegas tycoon Steve Wynn and his biggest investor and former best friend Kazuo Okada go head to head in court on Thursday in a case that has implications for the control of the $15 billion (S$18.5 billion) Wynn Resorts Ltd gaming empire.

The clash between the self-made billionaires - a Japanese businessman who made his fortune off pachinko machines and the American often credited with Las Vegas' modern-day makeover - is the culmination of a dispute that began a few months ago and that has transfixed the close-knit casino town.

Okada, who holds close to 20 per cent of Wynn Resorts and is suing to gain access to financial information, objects to an"inappropriate" $135 million donation to the University of Macau.

A resident of Hong Kong who made his fortune on pachinko machines, the 69-year-old is also proposing four potential candidates for the company's board, a move that could potentially give him command of five out of 12 board seats.

For now, Wall Street appears content to watch the fight unfold from the sidelines, with the shares of Wynn Resorts and Hong Kong-listed unit Wynn Macau Ltd largely unaffected. But analysts say the highly public spat, which has already escalated to fiery rhetoric from both sides, could weigh on Wynn's stock premium over rivals such as Las Vegas Sands Corp and MGM Resorts International.

"It does affect the premium. Wynn has had a premium over Sands and other operators because it is considered to be the blue chip operator with no corporate governance issues," said Aaron Fischer, Director of Gaming and Leisure Research at the CLSA brokerage in Hong Kong.

"With this kind of suit, it would reduce the premium, but the outcome, I am not sure."

Wynn, who has snagged OJ Simpson's former lawyer Robert Shapiro to lead his case, brushes off the claims from his business partner of 12 years, calling them "hyperbole" and "half truths," and is seeking to get the case dismissed.

Okada, chairman of Universal Entertainment Corp -an arcade-game manufacturer in which Goldman Sachs Group Inc has an 11 per cent interest - holds more than double the stake of Wynn held by its namesake.