The move is a change of policy by the government
Vietnam is to raise rice exports as it tries to maximise the benefits of rising global prices while, at the same time, guarantee domestic supplies.
The world's second biggest rice producer raised its 2008 export target from 4 million to 4.5 million tonnes.
Rice inflation has made it more profitable for farmers to grow more.
But Prime Minister Nguyen Tan Dung had been reluctant to raise exports until now because he feared domestic supplies would be jeopardised.
The price of rice traded on the Chicago Board of Trade has jumped 75% over the past year.
Asia's key rice producers have had to weigh up the needs of their own people, such as the amount and cost of rice available, and global demand for the staple crop.
Record oil and food prices have stoked fears that the world's poorest nations will face food shortages.
Earlier in the year, Vietnam announced limits to rice exports.
The government wanted to bring domestic prices down and secure its supply in the face of rising inflation, which hit 25% last month.
The price spike and speculation about a grain shortage lead to a run on supplies at Vietnam's supermarkets in April.
Analysts said that increasing exports could reassure world markets.
"The move perhaps could even help the global prices calm down a bit," said Jonathan Pincus, economist at the United Nations Development Programme.
But it is these high prices that encourage farmers to plant and harvest more rice.
Vietnam earned $1.2bn from exports in the five months to May, an increase of 94% over the same period last year.
"It's very attractive to export now and Vietnam certainly wants to earn that export revenue," said Mr Pincus.
The government said rice production would rise by one million tonnes to 37 million this year.
Since the start of the year, the country has shipped more than 2.2 million tonnes, a 19% rise on the previous year.
Asia's other top rice producers are also increasing output, with Thailand - the world's biggest rice exporter - harvesting 30% more crops.
Analysts blamed the sharp rise in rice prices on higher energy and fertiliser costs, rising global demand, loss of land to biofuel crops and drought conditions.