The boy, from Wahroonga, had complained of a sore stomach on Wednesday night and ate very little before going to bed, The North Shore Times first reported.

He woke up several times during the night in pain, his parents told police, before they took him to Hornsby Ku-ring-gai Hospital with stomach pain on Thursday morning.

After four hours at the hospital, the boy reportedly passed a stool and felt a little better, before he was sent home from the hospital about 7am. Doctors reportedly told his parents to monitor him.

But the boy deteriorated rapidly and he was rushed to Sydney Adventist Hospital at 2.15pm, police confirmed. He died two hours later.

NSW Police established a crime scene at the family's home, but have now deemed the death not suspicious.

The case has been referred to the coroner.

A corporate communications officer said North Sydney Local Health District (NSLHD)could not comment while the case was before the coroner.

NSW Health Minister Brad Hazzard has asked for a full report from the NSLHD about the boy's death.

"I can't imagine how his family are feeling and I express my deepest sympathy to them," Mr Hazzard said.

"In addition to the review that the Local Health District and hospital will undertake, I anticipate that the circumstances will be investigated by the Coroner."

On Tuesday Labor health spokesperson Walt Secord called for an independent investigation into the resourcing of Hornsby Hospital and a proposed upgrade.

"This is heartbreaking. It will be devastating and every parent's nightmare. Put simply, this is a tragedy," Mr Secord said.

"Imagine going home after seeking medical attention and then it seems to go all wrong.

"Hornsby Hospital was under enormous pressure and had more than 40,000 patients go through its emergency department every year," he said.

"Hornsby Hospital lurches from crisis to crisis. Doctors, nurses and allied health workers say they are working with one arm tied behind their backs due to the lack of the much-needed upgrade."