Dr Christopher Ryan, of the University of Sydney, spoke in front of almost 50 psychiatrists, psychologists and bioethicists, including eight students, at the "Coercion In Mental Health Practice: Compulsion, Autonomy, Persuasion" conference, at the Rydges Lakeland Resort.
Under transtasman law, a patient must be shown to be a danger to themselves or others, or incapable of looking after themselves, as well as have an abnormality of mind, before he or she can be committed and treated against his or her will.
Conference convener Dr Neil Pickering, a senior lecturer in bioethics at the University of Otago, said one of the arguments was the criteria meant many people who could be helped, were not being helped.
"They could benefit from medication, but unless you can show they are in some way a harm to themselves or others, you can't use the Mental Health Act 1992."
Dr Pickering said the psychiatric establishment was increasingly interested in caring for the mentally ill in the community, instead of in a facility.
"They are looking at using the minimal amount of coercion possible.
Treating people in the community is enabling them to have freedoms they wouldn't have in a hospital.
"Nonetheless, you want them to take their medications, which are believed to help them."
Dr Pickering said other speakers would discuss "informal coercion" by family, friends and psychiatrists, who put pressure on mentally ill people to voluntarily accept medication in order to avoid going under the Act.
It was the first conference of its kind organised by the University of Otago's Philosophy, Psychiatry and Psychology interest group and would conclude today.
Dr Pickering said the event would not have a formal outcome, but delegates would share the latest ideas with their colleagues around New Zealand, Australia, the United Kingdom and the United States.
