Acute shortages of trainee specialists are fuelling burnout among senior hospital doctors, whose own ranks are thinning.
According to the Association of Salaried Medical Specialists, there are 28 specialties where there are more consultants older than 55 than registrars (trainees) on track to replace them.
In 16 areas of medicine - including cardiothoracic surgery, general surgery, dermatology, paediatric surgery and psychiatry - 15 percent of the workforce was already pension age.
Association of Salaried Medical Specialists executive director Sarah Dalton was on the road this month, doing paid union meetings ahead of the upcoming contract negotiations. The shortage of registrars was dangerous, she said.
"It's causing senior doctors to have to cover for those missing RMOs (resident medical officers) and pick up tasks that are different to theirs, as well as their own work, which is exhausting. But it's also not particularly safe."
The union calculated hospitals were short 1140 full-time equivalent senior medical officers - 22 percent of the workforce - with half the existing clinicians reporting burnout.
Dalton said that was "frustrating" because those on the front line knew years in advance where the gaps would be.
"There are a number of services in New Zealand that lurch from crisis to crisis, and this is all well-known and it's always well-signposted by our members - senior doctors and dentists - well ahead of time."
However, the former head of Health Workforce New Zealand, Professor Des Gorman, said the colleges - which represent different specialties - were partly to blame for acting "like guilds" to protect members' interests.
"Over the years, the guilds have been very careful about limiting the number of trainees to ensure their private practices are not compromised in any way. So we are now suffering from the legacy of decades of deliberate under-training."
An attempt about 10 years ago to make it compulsory for district health boards (DHBs) to train specialists was stymied, he said.
"And the reason why the DHBs didn't support it is because they exist on an annual budget, and what happens in 10 years time is not their problem."
Listen to Ruth Hill's report here
Resident Doctors' Association national secretary Deborah Powell said she had never seen any data to support allegations that specialists were deliberately limiting the number of trainees.
"But for some of the colleges there certainly is an impression that may be a problem, even if it's predominantly derived out of Australia rather than New Zealand."
The biggest problem on this side of the Tasman had been the piecemeal approach to specialist training, she said.
"Each of the 20 district health boards really only cared about themselves. So when it came to training, if they had enough radiologists, they didn't really care that another DHB was struggling.
"Now we can look at it from a national perspective, and give that information to the resident doctors."
The National Resident Doctors Support Service - which is supposed to be in place by July next year - would finally show how many doctors were in training in each specialty and when they would become consultants, she said.
In a written statement to RNZ, Te Whatu Ora chief people officer Andrew Slater conceded it had been years since the health system was "able to articulate what we think the shortage in our current workforce is, and the workforce we need over the next decade".
Te Whatu Ora was committed to improving quality of its modelling, including in specific clinical specialties, and by service, he said.
"We intend to articulate a view of gaps in at least some key service areas in our next Health Workforce Plan in 2024."
Meanwhile, the recently released Health Workforce Plan 2023/24 would strengthen training pathways, including the government's announcement of 50 additional funded medical school places, the establishment of more training and fellowship roles and international recruitment "hubs".
Local services knew the "areas of pressure" and were working to fix them, he said.
Hospitals' costs of clinical training were funded by Te Whatu Ora out of baselines.
"As we come together as one entity we are increasingly taking a national approach to training, to ensure that locally, regionally and nationally our services have the workforce they need today, and for the future."