BEIJING -- Indonesia's central bank has started buying bonds in China's interbank bond market, expanding financial cooperation between the two countries, the Chinese central bank said on Monday.

China has allowed foreign central banks to invest in its domestic interbank bond market since 2010 as part of efforts to widen investment channels for foreign yuan asset holders and promote the international use of the Chinese currency.

China and Indonesia signed a three-year currency swap deal worth 100 billion yuan ($16 billion) in March 2009 and companies in the two countries are encouraged to accept export and import bills in Chinese yuan.

Besides central banks, China allows yuan clearing banks in China's Hong Kong and Macau and foreign banks that help settle cross border trade in yuan to trade in its interbank bond market.

The People's Bank of China made the disclosure in a statement on its website, www.pbc.gov.cn.