Universal Entertainment and its billionaire founder Kazuo Okada have filed a criminal complaint against Wynn Resorts and its CEO Steve Wynn in Japan on allegations of defamation.
The complaint marks the latest salvo in a long-running feud between the two former business partners.
Universal said in a statement on Wednesday that it submitted the complaint to the Tokyo District Public Prosecutors Office on April 24, accusing the US casino operator and its CEO of "defamation, harm to public trust and circulation of rumours" in relation to the publication of an investigation into Universal's conduct in the Philippines.
The investigation was commissioned by Wynn and made public in early 2012. Wynn said the criminal complaint was an attempt by Okada "to create a distraction from the investigations pending against him".
It said the complaint was related to a previously filed civil defamation case that a Tokyo court, ruling it should not be tried in Japan, dismissed last year. Universal is appealing that ruling.
Universal filed the civil defamation case after Wynn published its investigation into Okada in February 2012, alleging his company improperly offered gifts and entertainment to gaming officials in South Korea and the Philippines.
Universal has acknowledged spending a total of US$110,000 over three years on such outlays, but maintains they did not violate US anti-bribery laws.
Following the investigation, Wynn said Okada was unsuitable as a director of Wynn Resorts and redeemed Okada's 20 per cent stake in Wynn Resorts at a discount.
The battle between the former partners has been playing out in courts in the United States, Japan and the Philippines for more than two years. While Universal said in its statement that Tokyo prosecutors had accepted the complaint, it was unclear whether that would translate into an official investigation.
To date nothing has come of a similar criminal complaint filed by Okada against Wynn in the Philippines in December 2012.
The tussle between Okada and Wynn reaches a critical juncture next week, when a six-month stay on discovery in their US civil proceedings ends.
The judge in the case had put the civil proceedings on hold to allow US prosecutors to continue investigating Okada and his companies for possible bribery in the Philippines.
That criminal investigation centres on US$40 million in payments made by Universal affiliates to a politically connected consultant in 2010.