"The game and its rules are changing. You should be allowed to tamper with the ball after the 30th or 40th over," Afridi said.
"Only a few get to do some bit of ball tampering. If the weather is dry and hot then you can get some help from the pitch while bowling. But you also have to help the ball yourself.
"You have to tamper with the ball to make it swing on subcontinental pitches.
"It spells death for bowlers if you don't tamper with the ball. You can get some help from the pitch but even then you have to 'make' the ball," Afridi went on to explain.
Afridi was seen biting the ball during the fifth and final One-Day International against Australia [ Images ] on Sunday.
Meanwhile, he said ball tampering is nothing new and that only his method was wrong.
"There is no team in the world that doesn't tamper with the ball," added Afridi in his defence.
"My methods were wrong. I am embarrassed, I shouldn't have done it. I just wanted to win us a game but this was the wrong way to do it," he was quoted as saying by the local media.
"I apologise to all and everyone involved in the match and to the fans around the world. This will never happen again," he added.
Afridi pleaded for forgiveness and conceded that being the stand-in captain he should have been more careful.
"Being the captain I should have been a role-model for my players which I was not, but I hope I will be forgiven," he said.