Mega ICBC started operations in Sydney, Australia as a merchant bank, Cathay Finance International Ltd. on 15 August 1986. With the exception of checking accounts, Cathay Finance was providing most commercial banking services to individuals and companies.

New restrictions on deposit-taking were introduced after 1990 and Cathay Finance experienced high funds costs. In order to further expand operations in Australia, Mega ICBC decided to apply for a branch licence and on 15 October 1997, the bank commenced operations as a foreign branch under The International Commercial Bank of China Co., Limited, Sydney Branch ("ICBC Sydney Branch"). This was a first for Taiwanese banks operating in Australia. Under the foreign bank licence, Mega ICBC Sydney could freely accept deposits from nonresidents, and for residents, deposits. with a minimum initial amount of AUD250,000.

Mega International Commercial Bank Co., Ltd established Brisbane Branch on April 20, 1999, aiming to extends its international presence and provide banking service for local Taiwanese companies, and now it becomes the one of the most popular foreigner bank. Brisbane is the capital city of Queensland, also the sister city with Kaoshiung. Brisbane Branch located in Sunnybank which is near Sunnybank Plaza Shopping Centre.

Mega International Commercial Bank Co., Ltd. established Melbourne branch on 27 November, 2006, aiming to extends its international presence and provide banking service for local Taiwanese companies. Melbourne branch is located right on the Collins Street in the CBD. The branch provide various financial services, especially in commercial loan and syndication facilities.