The National Party believes a growing number of mental health facilities could be in jeopardy because there are not enough workers to staff them.
It follows reports an in-patient mental health unit at Christchurch's Hillmorton Hospital may close its doors as it has about half the workers needed.
Te Whatu Ora said the staffing situation for its inpatient extended care unit Tupuna was unsustainable.
Tupuna provides 24 hour care and support for people with mental health issues that require a longer stay in hospital than what its acute inpatient unit can provide.
Te Whatu Ora Waitaha Canterbury's specialist mental health services general manager Greg Hamilton said it is carrying a significant level of vacancies, "particularly within nursing".
"There is a national and international shortage of clinical specialists in mental health along with a national shortage of nursing staff across many regions and health specialities," he said.
"We continue to work proactively to ensure we can continue to provide safe care for patients and safe working environments for staff."
There is 9.25 full-time equivalent (FTE) nursing vacancies for the unit, which accounts for 48 percent, alongside gaps in clinical psychology and occupational therapy.
Te Whatu Ora said gaps are often filled by casual, pool and agency staff as well as staff from other areas.
A cutback from 15 to 10 available beds in the Tupuna unit happened last December with another bed removed in April.
"Despite the reduction in bed numbers, it continues to be difficult to cover all rostered shifts with the appropriate staff mix," Hamilton said.
"We are currently working through a change proposal with our staff."
It is proposed staff are relocated into either appropriate community placements or into another inpatient unit across the division.
"I think what we've got, there's a health minister, who's distracted on reforming the bureaucracy of the health system, spending hundreds of millions of dollars on health reform that's actually delivering worse outcomes," he said.
"And now we're learning that we've got a potential closure of much needed mental health beds in Canterbury.
"I think we're going to find that there'll be more closures around the country."
Data seen by RNZ showed more than 640 full-time vacancies in the mental health sector, for psychologists, psychiatrists and registered nurses at the end of June 2022.
Full-time psychologist vacancies across the country had grown by 140 percent in five years.
Doocey said the more existing mental health staff were stretched, the likelier they would burnout.
"When I talk to people with mental health, it becomes apparent pretty quickly, that the biggest obstacle for New Zealanders getting timely access to mental health care is lack of workforce.
"It's not good enough that we have large numbers of our mental health workforce who are leaving to other sectors because they're becoming work burnt out, covering many vacancies across our services."
