Kelly Clarke, 24, was with new husband Chase when she fell ill and was rushed to hospital on Wednesday with what was initially thought to be typhoid.
The family has since revealed she died of severe bilateral pneumonia, the Nine Network reported on Sunday night.
Ms Clarke, a recently-graduated registered nurse at The Children’s Hospital at Westmead, initially complained of stomach pain.
Within half an hour, her condition had deteriorated to the point where Chase knew she had to go to hospital.
“I spoke to her and she told me she was scared she was going to die,” he told Nine.
“I told her I loved her, we’re going to get out of here, everything’s going to be okay.”
Ms Clarke’s sister started a fundraiser to bring her home for emergency treatment, saying she had been placed in an induced coma due to organ failure and septicaemia.
Her brother Murray Shaw said Ms Clarke went into cardiac arrest five times within an hour and died before she could be medically evacuated.
Kelly Clarke, 24, was on a honeymoon with her husband Chase when she fell ill.Facebook / Kelly Clarke
“We are so shocked,” Mr Shaw wrote in a Facebook post.
“You beautiful girl and amazing sister you will be deeply missed.”
Chase described the agonising decision to direct medical staff to cease working on Ms Clarke.
“I said stop and pushed everyone away and me and her mother just held her,” he said.
In a statement provided to Nine, the family described Ms Clarke as “an amazing human being”.
“She was so young. She had her whole life ahead of her,” they wrote.
“She will be deeply missed and she was loved by all.”
The Children’s Hospital offered condolences.
0:00 Australia reaches peak flu season Share Australia reaches peak flu season
“Kelly was a dedicated nurse who loved working withchildren and will be greatly missed by her colleagues and patients,” a spokeswoman said in a statement provided to AAP.
Friends and relatives paid tribute to Ms Clarke on social media, with one co-worker remembering “an amazing woman, a brilliant nurse and such a kind and gentle soul”.
“She was one of the most beautiful, caring, giving people I have ever been lucky enough to meet,” another person wrote.
A Department of Foreign Affairs and Trade spokesperson said it was providing consular assistance “to the family of an Australian woman who passed away in Fiji”.