The Japan International Co-operation Agency will lend a total of $US420 million ($AU480.5 million) to Indonesia and Vietnam to assist these countries in developing climate action strategies.
Vietnam will receive a $US113 million ($AU130 million) loan, and Indonesia is to receive a $ US307 million ($AU351.2 million) loan.
Both countries, the Japan International Cooperation Agency stated (JICA), are particularly vulnerable to the consequences of climate change such as rising sea levels.
These loans, JICA says, are designed to help Indonesia and Vietnam implement infrastructure and policy to reduce their emissions and to enable them to respond to climate change related events.
The loans are co-financed by the French Development Agency.