The communist nation has also applied for a two-year stint as a non-permanent member of the Security Council.
Le Dung, a spokesman for the ministry of foreign affairs said on Friday: "To better contribute to the UN's general activities, Vietnam has decided to run for a non-permanent membership of the UN Security Council in the 2008-2009 term."
The country is also "preparing to join UN peacekeeping activities when possible", he said.
Foreign observers said the issue had been discussed for more than a year in Hanoi and indicated a significant softening in attitude towards the UN.
Vietnam was previously reluctant to join any multinational force after the country's intervention in Cambodia in 1979 was universally condemned by the international community.
One foreign diplomat, who wished to remain anonymous, said: "A year ago, they were saying the public opinion was not ready. Now they have moved forward. Anything Vietnam does to participate more effectively in the activities of the international community is a good thing."
He said he could not see any reason to oppose the idea. "It is positive if they look beyond the region, if they look at things in a more global perspective," he said.
However, some observers doubt that the Vietnamese would actually send armed soldiers. Medical or de-mining operations would be deemed more appropriate.Kofi Annan, the secretary-general of the UN, was due to visit Vietnam last month as part of an Asian tour, but the trip was called off at the last minute.