A patient who died in the waiting room of Rotorua Hospital's emergency department (ED) last month had been waiting three hours to be seen.

Distressed staff say she should have been seen within an hour, but the department was critically short-staffed.

Just two weeks earlier, ED staff had written to management just two weeks earlier, flagging their worries over excessive wait times.

The woman collapsed on 22 August in the middle of the packed waiting room and could not be revived.

Her cause of death has yet to be confirmed, but RNZ understands she had suffered a suspected cardiac arrest.

A doctor - whom RNZ has agreed not to name - said staff were devastated.

"That patient had waited three hours but should have been seen within half an hour to an hour.

"We were short-staffed. Everyone is just reeling. This is what we've been saying would happen, and now it's happened.

"It's devastating."

RNZ has previously reported on the shortage of senior doctors at Rotorua Hospital's ED, which threatened its hard-won accreditation to train more specialists.

Rotorua doctors had also been covering gaps at short-staffed Taupō Hospital, but were resisting attempts by management to formalise this arrangement, saying they were already stretched.

The Rotorua doctor said the pressures on ED were "predictable and preventable", and accused management of failing to act on clinicians' concerns.

"In this case, being seen sooner may not have prevented her death, but she would have received care and treatment."

New Zealand chair of the Australasian College for Emergency Medicine Kate Allan said emergency departments nationwide were under significant pressure from prolonged wait times and overcrowding.

"I would firstly extend my deepest condolences to any whānau or loved ones of anyone affected by this death, but also the healthcare workers and the other staff at the hospital.

"Obviously very tragic, especially if it's a preventable death.

"What it does show is that extended delays to care lead to poorer clinical outcomes which can include death."

Association of Salaried Medical Specialists head Sarah Dalton said the death was a tragedy.

"But I worry that events likes this could become more common where people who are very sick, who need to be seen, who need to be admitted to hospital, arrive and are not able to get the care they need in a timely fashion.

"In this case someone has died in the waiting room. That must be incredibly traumatic for all concerned."

Dalton said senior Rotorua doctors wrote to the district manager earlier last month (two weeks before the death) warning that long wait times in ED were putting patients at risk.

"Not only was it triage 1 and 2 patients [those with immediately life-threatening conditions] but also triage 3 patients, many of whom weren't being seen and could potentially be very sick.

"They got a response from the district manager saying 'I agree this is an absolute risk and agreeing to send those concerns up the chain."

She said the district manager agreed it was an absolute risk and promised to send those concerns up the chain to national level.

Dalton said it was not just EDs that were under pressure, but the entire hospital system.

"If there are no beds in the wards, you can't get people out of ED, and when ED stuffed full of patients - that makes them in turn slower to see patients waiting to get into ED.

"I really hope that we are not going to see more incidents like this but it's entirely possible that we will, based on the information we're getting back from our members."

RNZ has asked Health NZ about staffing in ED at the time of the death but it has yet to respond.

In a written statement, Lakes District group director operations Alan Wilson said Te Whatu Ora offered its sincere condolences to this patient's loved ones.

"We treat any adverse event involving a patient in our care extremely seriously, and we will conduct an internal review.

"As the case has been referred to the coroner, we cannot comment further at this time. "

-RNZ.