New Zealand's health watchdog has been challenged to fulfil his promise to hold a public debate about experimenting on unconscious patients without their prior consent.

In 2014, the Herald revealed up to 4000 critically ill or unconscious patients had been enrolled into clinical trials without prior consent since the 1990s.

In a new trial at Christchurch and Auckland City hospital intensive care units, researchers wanted to compare new and existing antibiotics. They said it was a low-risk trial and permission would be sought from relatives, followed by retrospective consent when a patient recovered.

Health and Disability Commissioner Anthony Hill at first said there was no mandate to change how trials were conducted with people not legally competent to give informed consent. Months later, he told health campaigner Lynda Williams, who wanted him to investigate the antibiotics trial, that he would hold a "fulsome public information and consultation process".


She told the Herald: "All I want is a public discussion so this is out there."

Ms Williams' comment follows Auckland University medical law expert Associate Professor Joanna Manning's challenge to Mr Hill in the Journal of Law and Medicine.

"In late-2014 [the commissioner] agreed to investigate this issue with a view to proposing law reform, but the promised public consultation has never eventuated," Professor Manning said.

The commissioner's office last week said the consultation was deferred to this year "due to continued growth in HDC complaint volumes and workload". A consultation document would be issued in September.

"Planning for the consultation, including reviewing international and local literature on these issues, process design, and the appointment of an expert advisory panel, is well under way.

"Informed consent lies at the heart of the Code of Health and Disability Consumers' Rights in New Zealand, which has now been extant for 20 years. Any change to those rights, or their application, should not occur without consideration of whether change is necessary and with due regard to ensuring sufficient protection of consumer rights."

Professor Manning proposed law changes to end the current legal vacuum and protect patients.