Defibrillators used in NSW’s ambulances have been failing at disappointing rates and are “by no means acceptable”, a director at the emergency service has told paramedics.

As NSW Ambulance on Tuesday publicly stood by the device after this masthead revealed the medical regulator had suspended its registration, a post from a senior officer cast fresh doubts over its reliability.

Marty Nichols, the service’s associate director of clinical practice, in March wrote a lengthy post to an internal forum with more than 4000 members, sympathising with officers reporting issues with the corpuls 3 and corpuls 3T devices, saying they were “right to be disappointed”.

Nichols’ post said the service had recorded 1229 corpuls failures in 2025 alone from the state’s 1500 operational devices. Noting some devices would have had multiple failures and others none, he said was “by no means acceptable”.

“I think it is fair to say we are all disappointed in the corpuls 3T,” he wrote. “I am not happy with the corpuls and hoped for more. The reality is the corpuls program cost over $50 million. We will have the corpuls device for at least the next five years. We all need to find a way to get the most out of the device.”

This masthead revealed on Tuesday the corpuls defibrillators, fitted in thousands of ambulances in NSW, South Australia and Western Australia, were suspended by the medical device watchdog and faced cancellation, for an undisclosed reason.

Alan Morrison, NSW Ambulance’s executive director of clinical capability, pushed back against that report on Tuesday morning, telling 2GB the devices were “safe to use and safe to provide care”.

“They continue to work to the standard we require,” he said.

In response to questions about Nichols’ post, a NSW Ambulance spokesperson said previous concerns about the device were addressed by the supplier after an inspection of every example in the state.

A “remediation” to fix motherboard soldering breakdowns was implemented in the 2025 financial year while an “automatic system reboot” problem on a “small number of devices” is also being fixed, a statement said.

“As a precautionary measure, every device within NSW Ambulance is also being upgraded,” it said.

Nichols, responding to one of hundreds of comments from paramedics about the $30,000 defibrillators, said in his post that while paramedics at large stations might hear of failure “almost every day”, that should be weighed against the 1.5 million callouts every year.

Last month, a paramedic wrote in a post: “At an arrest last night, the CO2 monitoring faulted and the inline cable was exchanged with another CorPULS [sic] to rectify the problem. Later in the case, the cable of this CO2 monitoring was cut.”

“Literally every shift I will either see corpuls capnography fail or discuss a recent time it failed with another paramedic,” wrote another paramedic. “The phrase ‘of course the end tidal didn’t work on the corpuls’ is a frequent refrain.”

Capnography and end tidal refer to the devices’ ability to monitor patients’ breathing – one of the many new features in the “state-of-the-art” devices touted by the NSW government in 2022 when it announced a $55 million program to replace older LifePak defibrillators.

“Lives which may not have been saved previously will now be saved because of these devices”, NSW Ambulance chief executive Dr Dominic Morgan said at the time.

Two years later, NSW Ambulance had to mandate that all ambulances continue to carry the older LifePak as a backup to the new corpuls, “to mitigate the risks of defibrillation failure resulting from a high voltage board failure on the corpuls 3T”, according to leaked safety notice. That requirement was lifted at the start of this year.

NSW Ambulance also issued safety alerts about the devices overheating and over-alarming. In one incident, a corpuls sounded its alarm 135 times.

The devices’ alarm go off so frequently paramedics are at risk of “alarm fatigue”, ignoring warnings from the device as their patients get sicker, according to a clinical safety notice issued by NSW Ambulance in March.

The NSW government, with South Australian and Western Australian authorities, insisted that continued use of the devices was in line with advice from the Therapeutic Goods Administration. The TGA has not explained why it suspended the registration for corpuls late last month.

Brett Simpson, NSW president of the Australian Paramedics Association, said it was encouraging that work was under way to address problems but issues were reported as recently as last weekend.

“There remains concerns amongst our members that new and previously undiagnosed problems are potentially arising every day given the rates of malfunction identified and fixes already implemented,” he said.

“These issues have been raised by paramedics and our membership, in line with some pretty spectacular reporting and statistics that have come out of this investigation.”

The union acknowledged the defibrillator problems were a “potentially unprecedented event” but NSW Ambulance and NSW Health should be transparent about “the exact extent of some of these failures”, he said.

In South Australia, the union said paramedics have struggled with unreliable oxygen probes, inaccurate systems to monitor patients’ breathing, and blood pressure monitoring inaccuracies.

The corpuls’ modular design allows paramedics to separate the defibrillator from the patient monitor.

Problems can arise when the modules are put back together, said Paul Ekkelboom, general secretary of the Ambulance Employees Association of South Australia.

“This can create challenges with reconnection and may impact the reliability of charging and defibrillation functions due to issues with the connection pins,” he said.

Federal independent MP Dr Sophie Scamps called on the TGA to reveal why it had suspended the defibrillators.

“Australians expect straight answers when it comes to lifesaving equipment used by our ambulance services, and they deserve complete transparency when questions are raised about its safety,” she said.

“Defibrillators are used in the most critical moments imaginable, and people rightly assume that any device carried by paramedics has met the highest safety standards.”

NSW Premier Chris Minns on Tuesday said he did not know why the TGA had suspended the devices, and that he had been informed that the model used in NSW ambulances was in working order: “I’ve got no reason to question that.”

“If circumstances change or there’s a software challenge with it, obviously, we [will] take the advice of the TGA,” Minns said in a press conference. “The NSW public should rest assured that paramedics are equipped with working equipment that will save lives.”

The NSW Shadow Minister Health Sarah Mitchell said the suspension was “not a small thing” and that monitoring the situation “isn’t a plan”.

“If there’s any doubt a defibrillator will work when a paramedic needs it most, the government should be acting now,” she said in a statement. “Ryan Park can’t keep hiding behind public servants every time there’s hard questions to answer.”

Mitchell said the public “deserve to know exactly what the specific concerns are from the TGA,” and said the NSW government should have that information and make it public.