Fullerton Financial Holdings Pte, a unit of Singapore’s Temasek Holdings Pte, bought a 15% stake in Vietnam’s Mekong Development Bank.

The purchase helped lift registered capital at the lender, based in the southern province of An Giang, to 3 trillion dong ($203.6 million) from 1 trillion dong, the Vietnamese bank said in an e-mailed statement today. The two companies also agreed on a plan that would allow Fullerton to increase the stake to 20 percent next year, it said, without giving a specific timeframe.

The investment allows Mekong Development to meet a central bank requirement to raise additional capital as the nation seeks to bolster lenders’ financial strength. The government on Dec 14 said it will extend the deadline for banks to boost their capital to 3 trillion dong by one year to Dec 31, 2011.

For Temasek, Singapore’s state-owned investment company, the stake adds to the unit’s banking holdings including shares of India’s ICICI Bank and PT Bank Danamon Indonesia.

Mekong Development had total assets of more than 8 trillion dong at the start of this month, with 40 outlets nationwide, the bank said in the statement.