SHANGHAI (REUTERS) - A Chinese central bank adviser sees the yuan superseding the US dollar as the global currency and predicts full liberalisation of China's capital account between 2015 and 2020, the China Securities Journal reported on Monday.

While the Chinese currency is already convertible under the current account - the broadest measure of trade in goods and services - the capital account, which covers portfolio investment and borrowing, it is still closely managed by Beijing because of worries about abrupt capital flows.

The newspaper said Mr Chen Yulu, a member of the central bank's monetary policy committee, wrote in a research paper recently that over the next 30-odd years to 2040, China should adopt a three-step strategy to achieve the internationalisation of the yuan, also known as the Renminbi.

The first decade would push the rise of the yuan in neighbouring countries, the second decade would be the extended use of the Renminbi in Asia, and the third decade would see the full convertibility and internalisation of the currency.

Mr Chen also wrote in the report that the liberalisation of China's capital account was inevitable and that in the long term this liberalisation would help financial stability.

Chinese officials have not given a timetable on a freely traded yuan, although the central bank has outlined the task of making the yuan "basically convertible" by 2015.

The article did not mention whether Mr Chen's view was based on China's economy overtaking the US economy in size as well.