Boxing legend, Manny Pacquiao has been complaining about poor officiating, calling for a review of his surprise loss to Jeff Horn.

But all that would not bother the newly-crowned world welterweight champion who has brushed aside Pacquiao's call for a review of his controversial defeat and threw down the gauntlet for a rematch.

Thousands joined a ticker-tape parade in Brisbane in honour of the former school teacher, who said he doubted if Pacquiao had personally backed a call to review the outcome of last Sunday's title bout.

"I don't actually believe that would be Pacquiao actually even saying that himself," the Australian told Channel Nine.

"Maybe it is his team around him. But Pacquiao seemed very humble in the way that he lost and thought the decision was correct.

"I am ready for a rematch. If he wants to come back and do it again, we will do it. That's up to him, he's got the option," Horn said.

Written off by most observers, the 29-year-old stunned the Filipino legend with his ultra-aggressiveness to earn a unanimous 12-round decision.

The result has been widely questioned, with many believing Pacquiao should have won.

The 38-year-old Filipino champion Wednesday backed a formal request by the Philippines' Games and Amusement Board for the World Boxing Organisation to review the decision.

"I love boxing and I don't wanna see it dying because of unfair decision and officiating," he said in a statement issued by his office.

"I had already accepted the decision but as a leader and, at the same time, fighter I have the moral obligation to uphold sportsmanship, truth and fairness in the eyes of the public."

In the twilight of a 22-year pro career in which he won world titles in an unprecedented eight weight divisions, Pacquiao had initially called for a rematch, but later said he would also "think hard" about retiring.

In Brisbane, with chants of "Hornet! Hornet!" ringing out, the Australian boxer was handed the keys to the city and told thousands of supporters he was ready for the next challenge.