"There is no resettlement. This is like being sent from one prison to another prison," he said.
Senathiraja's remarks came before a meeting at which Lynn Pascoe, the UN under-secretary for political affairs, is expected to push Mahinda Rajapaksa, Sri Lanka's president, to move towards returning the displaced Tamils.
Nearly 300,000 people have been living in makeshift camps in the north of the country since the government declared victory in its 25-year conflict with separatists from the Liberation Tigers of Tamil Eelam (LTTE) in May.
'Impatient and anxious'
Pascoe visited one of the camps on Thursday to assess the conditions faced by the displaced Tamils.
"I ... met with people in the camps who want to leave and return to their homes, but cannot do so, and are understandably growing impatient and anxious about their future," he said.
Sri Lanka has pledged to resettle 80 per cent of the people by the end of the year, but says it must clear thousands of landmines and weed out Tamil Tiger fighters hiding among the civilians before it can do so.
"In a practical sense, we cannot do it within a short time," Anura Priyadharshana Yapa, the government spokesman and media minister, said.
"I don't know when we can resettle 80 per cent. It all depends on how soon demining work is done, basic infrastructure is put in [place] and people have some livelihood support."
Pascoe acknowledged Sri Lanka's security fears in a statement he gave after Thursday's visit, but he urged Colombo to move quickly to return the displaced.
"We do actually know the security concerns. We are not oblivious to that. But it is very important as we see it to get people out into more normal circumstances as soon as possible," he said.
Aid groups have expressed concerns about the welfare of the Tamils being kept in the camps, particularly as the monsoon season approaches. 'Transfer camps'
Last Friday, the government announced that it had permitted 9,920 had been sent back to their homes in the north and the east.
But, in addition to Senathiraja's claims, a government official in the eastern district of Ampara told The Associated Press news agency that about 130 people who had been released from a camp were being held until they received security clearances and their homes were repaired.
In Trimcomalee, some of those who left the Menik Farm camp said that they were being housed in a government-run school.
"I'm disappointed to have left Vavuniya thinking that we can go home," M Shivanandan said.
Mahinda Samarasinghe, the human rights and disaster management minister, confirmed that some of the released were still in so-called transfer camps.
"They will be sent home soon, in a few days or weeks. There were rumours of them being kept for six months, which are total rubbish," he said.
Pascoe is also expected to discuss accusations of human rights violations during the conflict and attempts at political reconciliation on the Indian Ocean island.