Jeff Horn's upset victory over Manny Pacquiao may be re-scored but the Australian's welterweight world title is safe.

The World Boxing Organisation has agreed to a Filipino government department's request to review Sunday's fight after the legendary Pacquiao described the unanimous decision against him as unfair.

The Philippines Games and Amusements Board based its request on protecting boxing's integrity, citing possible miscalls by the referee and judges.

But the WBO reiterated the only hope of revoking the judges' decision rests on proving fraud in officiating the "Battle of Brisbane".