The central bank said on Tuesday that it will require Vietnamese travellers who bring more than US$5,000 abroad to declare it with customs authorities.

If approved by the government, the policy will take effect in July, replacing a current regulation that requires customs declaration on a foreign currency holdings of US$7,000 or more.

Vietnam is trying to control the use of foreign currencies in the country to restore confidence in the dong. According to the Asian Development Bank, dollars make up about 20 percent of money used in Vietnam.

Analysts at Viet Capital Securities said Monday that better stability in the foreign exchange market has helped reduce currency risk. The dong has actually appreciated from February, they noted. 

The dong gained 0.3 percent to 20,650 per dollar as of 3:16 p.m Wednesday in Hanoi, according to prices from banks compiled by Bloomberg.