Manila will revoke a license it granted to Japanese pachinko firm Universal Entertainment Corp. if allegations that it bribed a Philippine official to proceed with a $2 billion casino and hotel complex investment prove true, according to Philippine Amusement and Gaming Corp., which regulates gambling in the country.

Reuters has alleged that affiliates of Tiger Resorts Leisure and Entertainment, Inc., a subsidiary of Universal Entertainment, paid Rodolfo Soriano Jr., a former consultant to the gambling watchdog, $5 million while the firm was applying for a license.

Calling the allegations "serious," the regulator said it is asking the Department of Justice and the National Bureau of Investigation "to seek their assistance in coordinating with the U.S. FBI to find out the veracity of this report."

Soriano, who was a consultant during the term of the previous administration that ended in 2010, has been charged with plunder by the current administration, along with the regulator's chairman at the time, Efraim Genuino, for misappropriating at least 186 million pesos ($4.5 million) of the regulator's funds.

Universal Entertainment is chaired by billionaire Kazuo Okada.

"The group of Mr. Okada is a major investor in the Philippines and this is the reason why (the regulator) is giving them a chance to address all the issues affecting their provisional license for the operation of a casino facility," the regulator said. "Due process must still be observed."

It also reminded Universal Entertainment to settle a land issue at the proposed site near Manila Bay after a separate government body suggested that a constitutional restriction on foreign ownership had been violated.