The three-day final was scheduled to be played at the M A Chidambaram stadium here from Saturday.
The winner's purse and the trophy were awarded to Mumbai.
The runners-up prize money was not given to the Aussies as they have concern a walk over.
Tamil Nadu Cricket Association Secretary K S Viswanathan in a statement here today said that ''the Australian team have expressed their inability to take further part in the tournament reportedly due to domestic commitments. The tournament committee decided to award the winner's trophy to the other finalist Mumbai''.
The Aussies, making their debut in the tournament, had defeated Combined Districts XI in semis before emerging with a clean slate in league ties. Mumbai had made it to title clash round by virtue of 122-run first innings lead against Baroda.