Month-on-month increase brings five-month figure to 1.88%.
The consumer price index (CPI) in May rose 0.54 per cent compared to April and 2.28 per cent against December, according to the General Statistics Office (GSO).
The figure for the first five months is up 1.88 per cent against December and 1.78 per cent against the first five months of 2015.
Concerns remain over high inflation returning to Vietnam’s economy but increases this year are said to be from rising food and fuel prices.
The CPI in May was the highest in five years, with eleven types of goods rising.
Transportation saw the highest increase, of 2.39 per cent, due to higher fuel prices and bus ticket prices.
The second-highest increase was seen in housing and building materials, of 0.88 per cent.
Restaurant and catering services rose 0.36 per cent, cereals (rice, wheat, other grains) 0.68 per cent, and meat 0.38 per cent. The price of cereals has increased for five consecutive months.
Saltwater intrusion and drought in the Mekong Delta pushed up the price of cereals. Vietnam is also implementing a number of export rice contracts to China and Indonesia, pushing up prices.
Large rice stockpiles in Thailand will also impact on Vietnamese prices.