An investigation has found a woman died after a string of delays in assessments and treatments at Wellington Hospital.
It was also revealed not one consultant saw the 51-year-old; all the checks were left to junior doctors.
The Health and Disability Commissioner said several doctors and nurses hold a degree of responsibility for the flaws in the patient's care, who was taken to the emergency department by ambulance unable to breathe properly in 2012.
But Anthony Hill said those shortcomings happened because the hospital's systems were not working well.
He said there was no senior input from specialist clinicians.
His report found the woman's condition should have been categorised as 'immediately life-threatening' and should have been seen by a doctor within 10 minutes of arriving in the afternoon.
Instead, a nurse classified her case as 'urgent and potentially life-threatening', and it was more than an hour before she would be examined by a registrar in the emergency department, which was ''congested and overcrowded''.
About two hours later the patient was sent to the wards, but it was almost another six hours before the woman was checked by a general medical doctor.
Tests were taken and lab results were ordered.
But by nearly 3am - about 12 hours after first arriving by ambulance - the patient complained of chest pains. Twenty minutes later she lost consciousness and died.
Dr Shameen Safih, an expert who helped the Commissioner investigate the case, said:
"There was a slowness in reacting to alarming changes...there was a delay to receiving a critical treatment - calcium. That is not to say the death was preventable".
The report noted the woman had a history of health problems: she was a smoker, had type 2 diabetes, was obese, had problems with her liver, and had a history of asthma.
Mr Hill said: "I believe the care provided...represents a serious departure from expected standards".
Capital and Coast District Health Board apologised to the woman's family.
It said it had taken numerous steps to improve its services by boosting its medical workforce, including bringing in more senior doctors, who are are on duty for longer to supervise junior staff.