Men, women and children were given their first opportunity to leave the northern Manik Farm complex since their incarceration over seven months ago.
But many of them, their homes and villages destroyed in the country's long ethnic war, were expected to continue living in the camps.
N. Thirugnanasampanther, the senior civil servant in the area, said that since the gates were thrown open, many people had already left.
"Transport out of the camps is a problem, but people seem to be very happy," he said.
The United Nations had led international criticism of the camps, which it said were collective punishment for ethnic Tamils on whose behalf the Tiger guerrillas fought their 37-year-long guerrilla war.
Officials said over 100,000 out of about 130,000 still held in the camp complex 250 kilometres (160 miles) north of the capital Colombo left the camps on Tuesday, albeit temporarily for many of them.
"We have not received any assistance from the authorities to go and see our relatives,