The Office of the Ombudsman received more than 150 complaints from people living in direct-provision centres last year.
They included concerns about food, facilities and the standard of accommodation.
The Office of the Ombudsman examines complaints from people who feel they are unfairly treated by organisations that deliver public services.
In its newly released annual report, the watchdog reveals it received 152 complaints from people living in direct-provision accommodation in 2018.
Ombudsman Peter Tyndall says there were higher levels of dissatisfaction from residents in newer centres compared to the more established ones.
There were complaints from residents about food, facilities and the standard of accommodation.
The ombudsman claims the centres are unsuitable for longer-term occupation and calls for a formal resettlement programme to be put in place.
Mr Tyndall is also concerned about the number of asylum-seekers who are being put into emergency accommodation, such as hotels, because of the unavailability of direct-provision accommodation.
Over 1,600 complaints were made on behalf of children to the Office of the Children's Ombudsman last year.
It marks a slight decrease on the previous year, according to its annual report
However, Children's Ombudsman, Dr Niall Muldoon, says the same types of cases are always being raised.
He says the Government need to do more to address the challenges facing vulnerable children.
"We're hearing these issues from families that are really at their wit's end, whether it's a child looking for a new wheelchair, whether it's a child with autism trying to get a special needs assistant or medical support to go to school," he said.
"From my point of view, if we arrange the system with the child at the centre of it, we'd be able to budget for it, plan for it and maybe make sure that these things are accessed in a much easier way."
A complaint was made to the Ombudsman for Children's office after a 15-year-old girl was placed in an adult psychiatric ward.
After the OCO intervened, the girl was placed in an adolescent unit that was more appropriate to meet her needs.