The rate of mental health patients forced to undergo treatment is at its highest ever recorded.
Research by the University of Auckland shows the rate of community treatment orders for compulsory care has risen from about 60 per 100,000 in 2006 to 83 per 100,000 in 2011.
A person may be required to undergo compulsory treatment if he or she is found to have a mental health disability and deemed a potential risk to the community.
Senior nursing lecturer Anthony O'Brien says he is concerned by the increase and believes questions need to be asked about why this is happening.
Mr O'Brien says it could just be that recent data is more accurate and the rates of previous years were an under-estimate.
However, he says some clinicians are also becoming more cautious and are enforcing compulsory care to reduce risk.
The Mental Health Foundation shares Mr O'Brien's concerns, saying something needs to be done to cut numbers.
Chief executive Judi Clements believes compulsory measures are not the best way to deal with mental health patients.
"They can feel that they're not quite full citizens or full residents, that they're somehow second class - whereas people may be holding down jobs.
"It's not the way to think about equality and anti-discrimination, and build on the good work that's been done in New Zealand."
Ms Clements also believes the rise is due to clinicians being too cautious.