Commonwealth Bank of Australia agreed to buy a 15 percent stake in Vietnam International Commercial Joint-Stock Bank, becoming a strategic partner of the lender, according to a statement released Wednesday.

The Australian bank may raise its stake to 20 percent before Dec. 31, it said.

"Upon completion of this transaction, we expect to be a top five private joint stock bank in Vietnam," and CBA "will help us improve our competitiveness," VIBank Chairman Han Ngoc Vu said in the statement.

The Vietnamese lender, known as VIBank, had a pretax profit of VND205 billion in the first quarter, it said in a separate statement. Total assets reached VND55.86 trillion. The company expects pretax profit to reach VND907 billion this year.