Manny Pacquiao's world title fight with Jeff Horn will be “short and sweet” with a knockout likely, his trainer predicted on Tuesday, as his Australian challenger said he was “ready for war”.

The legendary Filipino, one of the greatest fighters of his generation, is widely tipped to triumph over the unbeaten Horn in front of an expected 50,000 people at Brisbane's Suncorp Stadium on Sunday.

“He (Manny) doesn't like to predict knockouts and so forth but I think it is going to be short and sweet,” trainer Freddie Roach told reporters at a press conference ahead of the World Boxing Organization (WBO) welterweight bout.

“I think it won't last too long and someone will get knocked out.”

Roach on Tuesday suggested the fight was a stepping stone for the eight-weight world champion to secure a rematch with American rival Floyd Mayweather, who outpointed Pacquiao in the “Fight of the Century” two years ago.

Horn's camp hit back, with the former school schoolteacher's promoters taking a dig at Pacquiao for spending most of the press conference looking at his mobile phone.

“Not only is Manny Pacquiao an eleven-time world champion… he is also a world champion texter, because he never gets off his bloody phone,” Dean Lonergan said.

Horn's trainer Glenn Rushton accused Pacquiao's camp of underestimating his 29-year-old challenger and said the so- called “Battle of Brisbane” would become the “fight of the year”.

“My vision for this fight is it will be a late stoppage. I think it is going to occur late in the fight after… all of these rounds. I personally believe this will be the fight of the year,” Rushton said.

“I do think Freddie and Manny are probably underestimating Jeff even though I know they say they are not because he is too experienced not to prepare properly.

“But I do think when they get out there, it's going to be so different. I think this will become Manny's toughest fight… we've trained as hard as we've ever trained for this fight, so we're ready for war.”

Pacquiao (59-6-2, 38 knockouts) briefly retired last year before making a comeback to win the WBO welterweight title against Jesse Vargas in November, as he juggles boxing with his duties as a senator in the Philippines.