Vietnam will announce a central rate for the dong/dollar each day starting from Monday, shifting from a fixed rate of 21,890 dong/dollar to allow more flexibility, the central bank said on Sunday.

"The policy will allow the foreign exchange rate to be (more) flexible ... in accordance with the demand and supply of foreign currency within Vietnam and changes in the global markets while still maintaining the State Bank of Vietnam's (SBV) management role," SBV said in a statement on its website.

Under the current system the dong trades around its fixed rate, which the central bank adjusts only occasionally.

Banks in Vietnam are allowed to trade the dollar within a 3-percent range above or below the central rate.