Vietcombank sold the dollar at VND24,505, down 0.10% from Thursday.
The State Bank of Vietnam raised its reference rate by 0.12% to VND23,915.
The dollar was stable on the black market at VND24,800.
It has increased against the dong by 0.35% since the beginning of the year.
Globally the dollar was steady on Friday, heading for its strongest weekly performance since July on scaled back expectations of steep and early interest rate cuts this year ahead of closely watched U.S. payrolls data later in the day, Reuters reported.
U.S. private employers hired more workers than expected in December, data showed on Thursday, pointing to persistent strength in the labour market that should continue to sustain the economy.
That helped the dollar shrug off weakness and against a basket of currencies, the U.S. currency was last at 102.39 in early trade on Friday. The dollar index is up 1% for the week, its strongest performance since the week ending July 23.
The dollar's rebound will be tested by the nonfarm payrolls report due later in the session. Economists polled by Reuters forecast that 170,000 jobs were created in December, fewer than the 199,000 in November.