MANILA- Philippines President Rodrigo Duterte on Friday defended the sale of an oil and gas concession to a firm controlled by a tycoon ally after a senate panel approved the filing of charges against energy ministry officials.

"I am convinced that this was a private transaction between private entities that must be respected," Duterte said, adding that the national interest has been protected.

Udenna Corp, a company owned by Dennis Uy, a friend of Duterte, acquired Chevron Corp's  45% in the country's Malampaya gas-to-power project worth $565 million in 2019.

Uy, the biggest contributor to Duterte's presidential campaign in 2016, has seen his empire rapidly expand through acquisitions and entry into businesses such as casinos, shipping and telecommunications.

A senate resolution on Thursday approved the filing of criminal and administrative charges before the anti-graft body against Energy Secretary Alfonso Cusi and 11 other energy officials in relation to the sale.

The energy ministry cleared the Udenna-Chevron deal in April 2021. It has called a graft complaint filed last year "groundless".

Duterte said he trusts Cusi, the president of the country's ruling political party, who will remain as the energy chief.

"I will not allow this valuable resource to be jeopardised and embroiled in the political antics of some members of the senate," Duterte said.

The Philippine senate doubted the technical and financial ability of Udenna to operate the project, and questioned the soundness of the energy ministry's financial evaluation of the buyer. The Malampaya project provides fuel for power plants with a combined capacity of more than 3,000 megawatts.

In response to a request for comment, Chevron said it "complies with all applicable laws and regulations wherever it operates or has business interests".

Cusi and Udenna did not immediately respond to requests for comment. Udenna has previously insisted Uy's association with Duterte has not given his businesses an unfair advantage.

(Reporting by Neil Jerome Morales; Editing by Kirsten Donovan) ((neiljerome.morales@thomsonreuters.com; +632 8841 8914;))