Former Hong Kong Monetary Authority chief Joseph Yam has joined the mainland's central bank as an advisor and said yesterday that the yuan can become the third pillar of the global monetary system as deteriorating public finances erode confidence in the dollar and the euro.

Yam, 61, was appointed as the executive vice-president of the China Society for Finance and Banking, a think tank under the People's Bank of China.

"Large budget deficits and public debt and structural problems in the financial system mean that the two pillars are not resting on sound foundations," he said at a financial forum yesterday in Beijing.