The International Monetary Fund is scheduled to formally meet later this year to review whether to include the Chinese currency in its Special Drawing Rights (SDR) basket.

The current SDR basket, which includes the US dollar, the British pound, the euro and the Japanese yen, is reviewed every five years.

Siddharth Tiwari, director of IMF's Strategy, Policy and Review Department, said on Tuesday that "we are also proposing extending the current SDR basket by nine months until September 30, 2016, to avoid changes in the basket at the end of the calendar year".

That can be costly for some SDR users to rebalance their portfolios, as markets and trading are typically thin at the beginning of the year. The current SDR basket expires at the end of 2015.

"An extension of nine months would also allow users to adjust to a potential changed basket composition should the executive board decide to include the RMB," he said.

But Tiwari indicated that the proposed extension, which will be decided by the 24-member executive board later this month, would not prejudge the timing of conclusion or outcome of the review.

In a report released on Tuesday, the IMF said that at the time of the last review in 2010, China met the gateway export criterion, meaning the use of renminbi, or yuan, in international trade, but the RMB was not included in the SDR basket because it was not judged to be freely usable, the second selection criterion for currencies.

The report said that across a range of indicators, the RMB is now exhibiting a significant degree of international use and trading.

The report points to several areas for further work that may help inform the board's final judgment. Those include additional work to close data gaps, refine the quantitative analysis for the freely usable assessment, and evaluate, in consultation with the membership and SDR users, whether the RMB would meet operational requirements, including as a result of continued liberalization measures that are being implemented by the authorities.

Tiwari said RMB is the only currency not currently in the SDR basket that meets the export criterion. Therefore, a key focus of the current review will be whether the RMB also meets the freely usable criterion.