BRISBANE, Australia -- Manny Pacquiao won't box Jeff Horn in a rematch of their WBO world welterweight title fight this year because the Filipino senator will be busy with government duties.

Australian promoters of the fight announced Pacquiao's unavailability for a proposed Nov. 12 bout on Friday.

Horn beat Pacquiao in a contentious unanimous decision in Brisbane on July 2. Pacquiao at the time said he wanted a rematch.

"On behalf of the Philippines government, [Pacquiao] will be part of a delegation that will visit China in the middle of his proposed preparation period for the fight," local promoter Dean Lonergan said. "Pacquiao is committed to fighting again in 2018 and a rematch with Jeff Horn for the WBO world welterweight title."

Manny Pacquiao will not be available for a proposed Nov. 12 rematch with Jeff Horn because of his duties as a Filipino senator. EPA/Dave Hunt

American contender Jesse Vargas, a former world titleholder, could possibly take Pacquiao's place for a fight later this year against Horn, the promoters said. Pacquiao beat Vargas in a unanimous decision last November in Las Vegas.

A week after his loss to former schoolteacher Horn, Pacquiao said he still disagreed with the unanimous decision that resulted in him losing the welterweight title, despite an independent rescoring of the fight confirming the unheralded Australian's win.

The WBO said in a statement then that three of the five independent judges who scrutinized the bout awarded it to Horn, one awarded it to Pacquiao and one scored it a draw.

The review concluded that Horn won seven rounds to Pacquiao's five. The fight took place before 51,000 fans at an outdoor stadium in Brisbane.