The Sri Lankan government says more than 200 people arrested after the end of the conflict with the Tamil Tigers have passed a university entrance exam.
Prisons Minister Chandrasiri Gajadheera said 363 prisoners sat the exam in prison.
Nearly 12,000 suspected rebels surrendered or were taken into custody after the government defeated the Tamil Tigers in May 2009.
Human rights activists say many are political prisoners rather than rebels.
A total of 210 detainees passed the exams, the minister said, and 40 of those qualified for university entrance.
Mr Gajadheera said two former rebels even qualified to enter medical college.
Chamil Jayanetti, of the Movement for the Release of Political Prisoners, told the BBC that the results proved that the government should release all political prisoners.
"This clearly shows that the Sri Lankan government has imprisoned innocent Tamil youth who have a brilliant future," he said.
The government released 100 former Tamil Tigers on Christmas Day and said that the total number of former rebels in government custody currently numbers 5,000.
Mr Gajadheera pledged to release those still in custody "as soon as possible" and said those found to be involved in atrocities would be charged soon.