Gerry Adams says Direct Provision is like prison without the armed guards.
He has compared his time in Long Kesh to the way asylum seekers are treated in Irish centres.
The Sinn Féin leader has visited Mosney where thousands of refugees are forced to live while their asylum applications are processed.
Under the system introduced in 1999, residents are not allowed to cook, work or be educated beyond the Leaving Certificate.
Mr Adams says it is a basic denial of human rights.
He said: "It was like Long Kesh without the watchtowers and the armed guards and the barbed wire. Because of the layout of the place, that's what it reminded me of.
"One in six have already been given permission to stay in the State, but they are still stuck in Direct Provision because they have nowhere to go, they've no home and no job and so on."