The number of people who did not receive specialist care within four months was six times higher in September last year than in July 2019, it found.
In an editorial on the study in the New Zealand Medical Journal, the authors said that had big implications.
“As access to hospital specialists declines, growing numbers of patients are left in limbo under the care of their GPs, adding further to the pressures on access to primary care services, and risks patients’ condition deteriorating and quality of life worsening,” they said.
The report said the number of people turning up to hospital emergency departments has grown by 22 per cent in the nine years to 2023.
And the proportion of them arriving with immediately or potentially life-threatening conditions has grown from a half to two-thirds, it said.
The union said the situation was much worse than in comparable European countries and urgent investigations were needed.
It said any change needed to be much wider than just the health system, addressing the problems that could contribute to bad health including poverty.