The Mental Health Commission has identified 16 non-compliances, eight of which were high-risk, in three mental health inpatient facilities.
The Inspector of Mental Health Services said she was concerned by high-risk non-compliances in two centres regarding patients' consent for treatment.
Dr Susan Finnerty said: "Consent to treatment is extremely important for patients and is a cornerstone of our mental health services.
"All patients have the right to be involved in decisions about their treatment and care and should be supported to make informed decisions if they are able."
Unsuitable premises was another key concern raised in three inspection reports published today.
Mental Health Commission Chief Executive John Farrelly said: "Finding mental health premises 'in a poor state of repair internally' is not acceptable in a modern health service.
"Unsuitable premises, cramped conditions and lack of personal space is also problematic for both staff and patients, placing an unnecessary extra level of stress on all concerned."