However, Waitemata heart specialist Dr Jonathan Christiansen, the head of medicine and older people's health, said the majority of heart attack patients in the west - those who suffered a less severe episode and were thus admitted to Waitakere - were not receiving "best practice" care and the aim was to improve this by sending them all to North Shore, or Auckland after hours.
"They are not getting the same access to care that North Shore patients are.
"They are placed in coronary care primarily as a place to monitor them before they get advanced diagnostics and treatment usually in a catheterisation lab ... International best practice says they should go to catheterisation as soon as possible," Dr Christiansen said.
This was a change that had occurred since the Waitakere coronary care unit opened in 2005, when "only a small proportion went to catheterisation".
Dr Ralph Stewart, chairman of the transtasman Cardiac Society's New Zealand committee, agreed that centralising the care to North Shore and Auckland City hospitals would be an improvement.
But another cardiologist, who asked not to be named, said: "It will be a downgrading of care given to patients and this requires a wide discussion with clinicians and not just something coming down from on high. You are doing away with what is the core of a general hospital."
West Auckland-based women's health advocate Lynda Williams decried the suggested cost-cutting and said the DHB should establish one of the heart diagnostic and treatment laboratories at the hospital.
Dr Christiansen said that would be expensive and low-volume catheterisation labs were not considered the best practice.