The battle over how Sydney will treat young kids needing heart surgery in the future has played out at a crisis meeting attended by leading health officials.

NSW comprehensive children's cardiac services are falling further behind other states, a leading pediatric surgeon has told a crisis meeting in Sydney.

Health workers, administrators and parents are split on a proposed move to cease heart surgery at one of the state's two premier children's hospitals - Sydney Children's Hospital at Randwick and the Children's Hospital at Westmead.

Westmead's chief pediatric cardiologist told key stakeholders on Saturday there was "no turf war" but concern for the state's ability to offer comprehensive surgical care to kids with heart issues.

"Comprehensive means antenatal to transition-to-adult services," Dr Phil Roberts told the crisis meeting.

"We are definitely behind the other states in Australia in delivering a comprehensive service.

"We do not have an adequate transplant service and we do not have an adequate primary hypertension service."

Westmead and Sydney Children's Hospital at Randwick merged under one banner nearly a decade ago.

Dr Roberts said the mathematics around low-volume, resource-intense cardiac services were clear.

"Really at this point, with how medicine has developed and trends in the western world, we would like to move away from isolated practice."

But Randwick-based pediatric cardiothoracic surgeon Peter Grant said the proposed merger of Randwick and Westmead had been "disastrous", poorly overseen by the board and led to broken promises.

"The overriding principle at the outset (in 2010) was that no service at either institution was to be diminished," Dr Grant said.

"However, like mergers in business, they are almost always disguised takeovers.

"The cardiac surgery program at Randwick has been systematically run down."

NSW's eight million people needed two top-level pediatric hospitals offering cardiac surgery, Dr Grant said.

"The waiting times at Westmead have been consistently three times that of Sydney Children's Hospital."

Health Minister Brad Hazzard, NSW Health Secretary Elizabeth Koff and the head of the cardiac planning steering committee, former NSW Health director-general Michael Reid, were among those to attend the meeting.