Vietcombank sold the greenback at VND25,470, up 0.04% from Monday.
The State Bank of Vietnam raised its reference rate by 0.04% to VND24,258.
The dollar dropped 0.19% to VND25,660 on the black market.
Globally the Australian dollar sank towards a four-month low on Tuesday after the central bank softened its tone on the policy outlook, raising expectations for an earlier interest rate cut, Reuters reported.
The U.S. dollar was steady against its major rivals and edged to its strongest this month versus the yen as traders looked ahead to a reading of U.S. inflation on Wednesday for further clues on the pace of Federal Reserve easing.
The Aussie sank 0.71% to $0.63955, and earlier dipped to $0.6380, putting it in striking distance of the low of $0.6373 on Friday, a level that hadn't been seen since Aug. 5.
The U.S. currency eased 0.07% to 151.11 yen after earlier climbing to 151.55 yen for the first time since Nov. 28.
The U.S. dollar index, which measures the currency against six major peers, was steady at 106.16.