The refinancing rate will be cut to 13 percent from 14 percent and the discount rate reduced to 11 percent from 12 percent effective Wednesday, the State Bank of Vietnam said in an online statement released late Tuesday.
Last week, official figures showed growth slowed to 4.0 percent in the first three months of 2012, its slowest rate in three years as the government prioritised fighting inflation.
The rate was well down on the 5.57 percent posted in the same period last year and the weakest since the 3.1 percent recorded in the first quarter of 2009.
The Wednesday rate cut comes a month after a one percent cut in the refinancing rate -- charged on loans to commercial banks -- which was the first reduction in nearly three years.
The bank last cut the rate, one of several key monetary policy tools, in April 2009, to seven percent.
Since then, it had repeatedly hiked rates, most recently in October, in a bid to rein in soaring inflation, which peaked at an annual rate of 23 percent in August.
Inflation fell in March for the seventh consecutive month, with the consumer price index up 14.15 percent -- still high, but the lowest level in a year.
Last year, the country's GDP growth rate was down to 5.9 percent from 6.8 percent in 2010.
The government is targeting economic growth of six percent for 2012, up slightly from 2011, and has said it aims to bring inflation down to single digits.
Last year, Vietnam refocused efforts from economic growth to stabilisation to deal with price rises and other challenges, including dwindling foreign reserves, a yawning trade deficit and downward pressure on the dong currency.