South Korea President Yoon Suk Yeol and Indonesian President-elect Prabowo Subianto on Wednesday agreed to expand cooperation on defence, electric vehicles and infrastructure, South Korea's Presidential office said.

The two spoke by phone months before Prabowo is due to take office. The stakes are high for South Korea, which has an unprecedented - and rocky - arrangement with Indonesia to develop a next generation fighter jet and is also hoping for a cut of lucrative infrastructure projects.

"The President and President-elect Prabowo agreed to continue to expand strategic and future-oriented cooperation in fields such as defence industry, electric vehicles, and infrastructure even after the new Indonesian government launches October this year," the South Korean statement said.

The two countries have been working together to develop the KF-21 supersonic fighter jet, South Korea's homegrown fighter jet that is partially backed by Indonesia.

The KF-21, developed by KAI, is designed to be a cheaper, less stealthy alternative to the U.S.-built F-35, on which South Korea relies.

The two nations also recently signed a memorandum of understanding to promote the use of their currencies for bilateral transactions, such as current account transactions and direct investment. (Reporting by Cynthia Kim and Josh Smith; editing by Miral Fahmy)