A proposal for psychiatrists to work seven consecutive nights because of Covid-19 has been slammed as exploitation of a national health crisis to implement an unsafe roster.
But Waikato District Health Board says its new roster was a short-term reaction to the coronavirus pandemic, and had attracted "no shortage of volunteers".
The Association of Salaried Medical Specialists said Waikato DHB's attempt to start the roster amid the coronavirus pandemic was concerning.
The union for senior doctors' chief executive Sarah Dalton said the move was not properly consulted with the union and they were "really unhappy" about the proposal.
"It's just too fatiguing and fundamentally in our view not safe to ask staff to work seven nights in a row," Dalton said.
"Even one night of broken sleep - and that's just waking up or taking a phone call let alone being up all night - that takes two nights of uninterrupted sleep to recover from that sleep debt.
"Imagine the massive sleep debt that someone accumulates working seven nights in a row."
She said a maximum of three nights in a row was generally agreed as the safe number of consecutive nights.
"It's not healthy for staff and it's probably not ideal for patients either if you're having to be cared for and have decisions made about you by someone who's on night six or seven of a seven-night run."
Dalton said the reasons for the proposal were unclear.
"But we would take a very dim view of any attempt to use a national emergency situation to leverage backward or unsafe approaches to staffing. We would fight it hard."
Dalton said calling for volunteers was divisive and the union was concerned that the DHB "appeared to threaten to direct the SMOs if sufficient staff didn't 'volunteer'."
"We don't like taking a volunteer approach because it has the potential to divide staff. And we would certainly frown on any attempts to use a crisis to dictate the new normal."
The DHB wrote to mental health staff on Tuesday calling for volunteer senior medical officers to undertake the new roster.
The email, seen by the Herald, said there was a need to establish a night shift for senior doctors as well as a change to the junior doctors' roster.
Sent on behalf of Waikato DHB mental health and addictions director of clinical services Dr Rees Tapsell, it said the new roster was needed "because if we are to avert admissions, as we must, it is important to have some of our most senior people making these decisions with adequate support for alternative strategies".
The shift would run from 11pm to 8am and psychiatrists would work seven nights on and have and seven days off.
"We are looking for SMOs interested in participating in this roster. If we cannot get sufficient volunteers then the clinical director group will participate in this roster and we may then also need to make some directions around this."
A DHB spokesman said the pandemic was outside "business as usual", creating the need to redeploy senior doctors.
When asked why the DHB would need to "avert admissions" the spokesman said the Henry Rongomau Bennett Centre has experienced record levels of occupancy over recent years.
"While occupancy has dropped somewhat since the Covid-19 pandemic began, experience of other emergency situations tells us this is temporary and we will again see record presentations to acute services.
"Having more senior staff, not just SMOs, at the front end of the service increases the efficiency and appropriateness of decision-making, including decisions about admissions to hospital."
During a night shift they would be on site and on duty.
"They are there to more closely support the other members of the after-hours team.
"They will not be working the next day and they have one week off following any week of nights."
The spokesman said senior and junior doctors required on site would have access to rest facilities as necessary.
When asked about protecting the health of frontline workers from sleep deprivation amid Covid-19 the spokesman said the roster was "only intended to be used in the short-term during this pandemic event".
He said the DHB had discussed the proposal with a union representative who "acknowledged that we are in a national emergency and that we must make some short-term changes to the redeployment of SMOs".
When asked if the DHB had ever tried to introduce this roster previously, the spokesman said: "Night rosters have come up previously in discussions and whilst some SMOs support this idea we have not moved the idea further as others do not".