However, the government has failed to make adequate welfare provision for the 136,000 Tamil civilians it plans to release from internment camps, rights activists and opposition parties said.
An aide to the president also confirmed a pledge to close the facilities, reported BBC Online.
This follows earlier promises by the Sri Lankan government to free at least 80% of the population of the camps within 6 months of the end of the war. It has been over 180 days and less than half the detainees have been released.
International pressure is mounting to release the remainder from what rights groups are calling a form of collective punishment.
The latest government announcement was made by the special adviser to President Mahinda Rajapaksa, his brother Basil, on a visit to the largest camp, Menik Farm.
Addressing a group of ‘displaced’ people, Rajapaksa said that from 1 December the camps would no longer be closed sites.
“We will allow complete freedom of movement,” he told those held in the Menik Farm camp.
People will now be free to leave them for a day or two at a time, to visit friends and relatives, for example, he said.
Although they will not be able to leave permanently, he reiterated the government's pledge to resettle those displaced by the end of January.
Rajapaksa said the military had agreed that the detainees could be released because they no longer posed a security threat.
"The decision was taken as part of government moves to improve the rights and privileges of internally displaced people," said a statement posted on the government's website.
While observers welcomed the announcement, they warned the government that it must organise a structured resettlement programme.
"We are insisting that the International Committee of the Red Cross or the UNHCR (United Nations High Commissioner for Refugees) should be present when people are resettled," Nimalka Fernando, spokeswoman for the Democratic People's Movement, was quoted as saying by AFP.
She said the government's plan to "haphazardly" send the civilians back to their villages was "seriously flawed".
The main opposition United National Party (UNP) said no long-term help in providing themselves with food or rebuilding their homes and livelihoods was being offered to the civilians who had already left the camps, let alone those still waiting to leave.
"People are to be moved out without proper welfare facilities," UNP general secretary Tissa Attanayaka said in a statement.
The camps were set up to contain the Tamil civilians who fled the war zone during the last stages of the war with the Liberation Tigers.
Those displaced by the fighting were forced into the hastily built camps, with the funding for the camps coming from international aid.
The barbed wire enclosures at Menik Farm, which are guarded by the Army, have been among the most controversial aspects of the government’s dealings with the Tamils.
Sri Lankan authorities insist the camps meet international standards, but they have refused to allow reporters access — except on brief tours organised by the Army.
Many of those interred in the camps complained about poor food and sanitary conditions, reported the BBC.
Human rights groups criticised the detention, claiming it was an illegal form of collective punishment for Tamils.
There was also heavy criticism of the limited access permitted to the camps, with media heavily restricted and even aid agencies having problems gaining admittance on some occasions.
The UN, diplomats and charities have criticised the screening process, saying it is not transparent.
The government has also said that more than 1.5m mines must be cleared and basic infrastructure needs to be in place to allow people to return home.
Opposition parliamentarians in
