"I think after four or five years this will be the most popular game, (compared to) 50-over games and Test matches," he said on Thursday.
"Now it's very popular. After one or two years it will be the most popular game."
Inzamam had just captained Pakistan to a 56-run loss against Australia A in the first Twenty20 International to be played in Australia.
Twenty20 cricket, as the name suggests, allows for just 20 overs a side and imposes a number of rules to keep play flowing quickly.
It has proven very popular in England and capacity crowds of more than 20,000 watched the inagural first-class match between state teams Western Australia and Victoria on Perth on Wednesday as well as the international at Adelaide Oval on Thursday.
"Life is so busy and people have no time to see the five-day game, when there are soccer games that are one-and-a-half hours," Inzamam said.
"People like this game and the players are also enjoying the game."
But Australia A captain Brad Haddin said while 20-over cricket was entertaining and had a future, he doubted it would take over from Test or One-day cricket.
"I think Test cricket will always be the most popular form of the game," Haddin said.
"I think this form of the game will be a form of entertainment, where people can come and watch and only be down here for three hours, but I still think Test cricket is the most popular form of the game."