The Lao Cai Province market surveillance department said Wednesday the restaurant had charged them VND925,000 for their meal when they went there on New Year's Day while the actual price was VND307,000.
They had ordered of pork, chicken and rice dishes, water and soda, and were charged VND495,000 for one of the roasted meat dishes.
The tourists spoke about the incident on social media, questioning the prices.
The Sa Pa people's committee took cognizance and asked the market surveillance team to look into it.
Sa Pa is a popular tourist destination in Vietnam's northern highlands. During the New Year holidays its hotels and motels reported over 80% occupancy.