HONG KONG (AFP) - Manny Pacquiao's trainer Freddie Roach was involved in a physical bust-up with Brandon Rios' team as the build-up to this weekend's title showdown turned ugly on Wednesday.

Footage showed an angry, expletive-laden row followed by Rios' conditioning coach Alex Ariza kicking Roach in the chest as the veteran trainer steps towards him.

Roach had taken Rios' team to task for apparently overshooting their allotted time at training facilities in Macau, which Pacquiao was due to use.

Ariza later admitted kicking Roach, who is 53 and suffers from Parkinson's Disease, but said he had no regrets ahead of Sunday's World Boxing Organisation welterweight title fight.

"You could see the way he (Roach) came in, he wanted to kick something off," he said on the footage posted on YouTube by SecondsOut.com.

"He cocked his fists back and to me, that's a sign of aggression coming towards me. He got physical and he came at me, and yeah, he got a front kick in the chest.

"When you raise your fists at somebody, the other person has a right to defend themselves and that's what I was doing."

Roach said Ariza "kicked me like a girl" as the two sides continued to taunt each other beside the training ring set up in the Macau gym.

The two camps have a history after Rios did an impression of Roach that infuriated the celebrity trainer because he said it mocked his Parkinson's Disease.

Pacquiao, 34, is hoping to bounce back from two successive defeats when he faces the 27-year-old Rios on Sunday morning.

Top Rank promoter Bob Arum shrugged off the altercation between the two camps.

"We have a fight already and it's still a few days out," he said, according to Yahoo Sports.