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 husband, Chase Clarke, told Fairfax she was 'outspoken, smart, courageous, and had the biggest heart'. She was told she had contracted typhoid.
'You (were a) lovely girl and awesome sister you will be deeply missed, ' he wrote.
Mr and Mrs Clarke were married in April and had been in Fiji for their honeymoon and to attend a friend's wedding.
However, just hours later, Mrs Clarke's condition deteriorated and she was rushed to hospital in Lautoka.
It was initially suspected that she had contracted typhoid, however blood tests revealed that the disease was not the cause of her death.
"Kelly was a dedicated nurse who loved working with children and will be greatly missed by her colleagues and patients", a hospital spokesperson shared.
The page has raised over $50,000 while will be donated to Kelly's grieving husband.
Mrs Clarke finally succumbed to her illness at 10.40pm on Friday night, less than an hour before a medevac team arrived to airlift her to Sydney.
"I told her to be strong, that I was coming straight back and to rest up because she needed her strength".
The couple had been holidaying on the South Pacific island in the lead-up to Mr Clarke's best mate's wedding and had conquered a number of phobias together.
"She loved kids and loved her work as a nurse and was getting great feedback from work". The diagnosis was only delivered after Kelly passed away on Friday.
'This terrible situation shouldn't have happened, ' Mr Clarke said.
Clarke said the family is waiting for approval to transport her body back to Australia. The cost to get the young woman's body home is expected to be over $60,000 and will be covered by a combination of insurance and funds from the Department of Foreign Affairs.
Her parents Graham and Karen Shaw have flown to Fiji and have chartered a private jet to fly her body home but are awaiting approval from Fijian authorities which could take several days.