The Department of Health has said it will take action to deal with the crisis facing some mental health patients at Muckamore Abbey.
The patients are all in Muckamore Abbey Hospital
A BBC investigation found people with severe learning disabilities are being kept in hospital as there is no money to care for them in the community.
One man remains in the unit 10 years after his treatment ended.
The Department of Health said the current situation was "unacceptable" and would be looking into it.
Andrew McCormick, permanent secretary at the Department of the Health, said its policy had enabled a significant number of patients with learning disabilities to be resettled in the community.
But he said the trust and the boards had "worked very hard to try and find a better solution".
"If there was a quick-fix available, we would have found that," he said.
"The minister has asked me to look at this immediately to appoint a senior official within two weeks to secure information about the total situation... then we can look at what we can do.
"But, there aren't easy options available - we may have to find a difficult option and adopt it."
The BBC has learned that well over 100 adults with learning disabilities have had their discharge from hospital delayed for an average of three and a half years.
The patients are all in Muckamore Abbey Hospital, County Antrim.
Alliance Party leader David Ford said urgent steps need to be taken to address the matter.
"I think there are three things to be done: the Human Rights Commission should conduct an investigation on the apparent breach of individuals' rights," he said.
Families and politicians have called for an inquiry
"The trust needs to look at its functions to see if it can do something better at the moment, and the minister needs to commit to the funding recommended by the Bamford Report on mental health."
The father of a teenage boy at Muckamore said his son, who has learning difficulties, and other children were "forgotten about".
"It is a hard place for children and it is difficult for parents. There are not the facilities outside to help children when they come out," he said.
"He has been there since September, and he could be there for another six months - it is very hard for a young boy of 13-years-old.
"I would like to see more money spent up there. They are trying to demolish some of the older units, but facilities for young children are badly needed at Muckamore."
BBC NI health correspondent Dot Kirby said: "The man still there after 10 years is one of 118 people whose treatment is complete - but his discharge has been delayed because there's nowhere suitable for him to go.
"For over 10 years, there has been a policy that no-one should live long term in hospital.
"Hospitals like Muckamore should be used to assess and treat people prior to their discharge."
She said it would be wrong to suggest that no progress has been made.
"Over the years, the population of Muckamore has more than halved as people have been moved to more appropriate accommodation."
Now some have expressed concern that these people's human rights are being abused.