Junior doctors are on another two-day strike but DHBs say they are well prepared and confident of progress in resolving the dispute.
An estimated 1700 doctors are off the wards from 8am until early Thursday in their row with their employers over proposed changes to sections of employment contract dealing with rosters.
The strike is the doctors' third 48-hour industrial action within a month, and yesterday the union, the Resident Doctors' Association, gave notice of a fourth strike at the end of the month.
A woman whose teenage daughter's surgery has been postponed because of the action is desperately hoping district health boards and junior doctors settle their dispute soon.
The Canterbury mother, who RNZ is calling Joan, said her teenager had painful benign bone tumours in two parts of her body. She said her daughter was originally given a date of 17 January for her surgery and the delays had left her in agony.
"It comes with night pain so what you find yourself doing is that you're up most of the night in the pain and then you're sleeping most of the day when you can manage that pain better."
Some senior doctors have demanded the junior doctors' union and the district health boards settle the row - both for the sake of patients and exhausted senior doctors who are filling in.
In a letter sent last Wednesday, senior doctors at Palmerston North Hospital wrote to their DHB saying the protracted nature of the dispute had led them to have serious concerns about fatigue among senior doctors. They said they were also worried about "the resultant increasing difficulty in covering the acute hospital duties normally performed by RMOs [resident medical officers, or junior doctors]".
DHB spokesperson Peter Bramley said he was not aware of the letter, and there were daily planning meetings to ensure safe services can be provided.
DHBs are well prepared to deliver emergency care and support those who are acutely unwell, he said.
"DHBs are hugely appreciative of the way that senior doctors over the last two strike periods - and they will again today and tomorrow - step up and support safe care.
"They'll pick up either additional duties or they'll step into the role of the RMO."
MidCentral District Health Board has responded to senior doctors' criticism that Palmerston North Hospital had tried to maintain non-urgent surgery during the last strike leading to an exhausting workload.
Chief medical officer Kenneth Clark said the hospital tried to do too much during the last junior doctors' strike, and had made changes.
"We were faced with much higher clinical demand than we expected and in retrospect our amount of elective work that we did during the second industrial action was a little too much. We've taken steps to pare that back very considerably."
Mr Bramley said there were proposals on the table for mediation on Friday and the DHBs were confident the bargaining teams would make progress.
"We're confident we can make progress because we've already found a way through this with the other union representing junior doctors."
Junior doctors have acknowledged everyone is under pressure because of ongoing strike action, but David Munro, an advocate with the Resident Doctors' Association, said their determination was a strong as ever.
"Clearly in negotiations that puts the pressure on the parties. I think we will be working very, very hard to try and find a solution when we meet this coming Friday."
Today's strike is taking place across all district health boards except Nelson and West Coast. The union lifted the strike notice in the Nelson region due to the bush fires.