Bay of Islands Hospital will not be able to take any new admissions until Monday because of a shortage of doctors, according to hospital insiders.
New patients will be transferred to other hospitals.
Angry doctors have told RNZ this is "not a sudden crisis" - but Health New Zealand was warned two months ago this was going to happen, after they slashed locum rates.
As of Wednesday, only two of the doctor shifts on Friday and Sunday at the hospital in Kawakawa had been filled, and only one of the four doctors needed on Saturday had been found.
Bay of Islands hospital unable to take new admissions
However on Thursday morning, Health NZ confirmed it was still looking to fill two shifts and had contingency plans in place.
A doctor who has regularly done locum stints at Kawakawa said with a day's travel on either side and all the other costs involved, it was not worth his while under the reduced pay-rates.
"I just can't justify five days of my personal time to come up and do three days of work when you're only going to pay me two-thirds of what I got. I can do one day of work in my own town and earn the same."
Te Whatu Ora is trying to enforce a single pay-rate nationwide, which has seen rates cut by up to 47 percent in some cases.
Health NZ trying to 'break reliance on locums' - union
Association of Salaried Medical Specialists head Sarah Dalton said physicians from Whangārei Hospital had been asked to fill in and offered more than the new locum rate.
She said that put them in an awkward position.
"Rural hospital qualified specialists have quite a broad scope of practice because of the very nature of rural hospitals - you're dealing with a wide range of people. So by asking physicians from Whangārei Hospital to go up and cover, they're effectively asking those doctors to work outside their scope of practice."
Te Whatu Ora appeared to be trying to "break the reliance on locums" - which was a huge cost to the system - but without treating the underlying problem, she said.
"The only way long term to deal with it is to significantly improve terms and conditions for permanent staff, and be prepared to staff up more."
The locum, whom RNZ has agreed not to name, said Health NZ still needed locums and locum agencies.
Over-worked hospital staff could not be expected to find cover at short notice, organise travel and accommodation and everything else required.
"If the hospitals think they can do the job of the agencies, they're sadly mistaken. I do extra duties here at my hospital and I'm still waiting to be paid for one I did eight weeks ago."
Bay of Islands Hospital is a 20-bed facility doing surgical, children's health, medical and maternity care.
Its busy emergency department treated 12,000 patients in the last year, including time-critical, life-threatening injuries and medical problems.
Dalton said the Northland region was "regularly breaking medical staffing requirements for rural hospitals, leaving nurses unsupported".
"And they're not communicating this with local communities. They didn't communicate the shortages at Dargaville Hospital (which had its overnight medical cover replaced with telehealth last month) and they're not communicating the forthcoming shortages at Bay of Islands. So people will be rolling up, expecting a certain level of care and it won't be there."
Patient safety 'paramount' - Te Whatu Ora
Health New Zealand group director of operations for Te Tai Tokerau, Alex Pimm, said staff absences were "not uncommon" due to illness or leave, and the organisation planned ahead for this.
"While some doctors from Bay of Islands Hospital will be on leave this weekend, we have contingency plans in place to ensure our service continues as we look to fill two remaining shifts.
"The general ward will remain open, with reduced beds if necessary, however we want to assure the public that if they need hospital level care, we are here, and our Bay of Islands Hospital emergency department remains open."
The other three hospitals in the region worked closely together to meet patient needs, he said.
"The safety of our patients and all staff is paramount."
For non-emergency healthcare, people are urged to phone Healthline on 0800 611 116
Rural residents can ring Ka Ora - phone 0800 252 672 between 5-8pm on weekdays, and 24 hours a day on weekends and public holidays to speak to a nurse or organise a video consultation with a doctor.