A heartbroken mother is fighting to keep her young daughter alive after the toddler was diagnosed with a rare tumour.

Leanne Shaw's two-year-old daughter, Ava, was diagnosed with Neuroblastoma, which is a very aggressive form of childhood cancer, in April.

The Melbourne mother, who was 33-weeks pregnant at the time, said she was shattered when doctors told her Ava would need to undergo extensive chemotherapy.

Ava, was diagnosed with Neuroblastoma, which is a rare and very aggressive form of childhood cancer

Leanne Shaw (pictured) said she was shattered when doctors told her Ava would need to undergo extensive chemotherapy

Ava was required to undergo extensive treatment including chemotherapy to attack the tumours

'She had been an absolutely perfect, happy, bubbly little girl until she turned two,' Ms Shaw said

'She had been an absolutely perfect, happy, bubbly little girl until she turned two,' Ms Shaw told Seven News.

Doctors initially told Ms Shaw and her partner, James, that Ava had a viral infection. During a second visit, physicians said the toddler was suffering from a UTI and prescribed antibiotics.

Soon after, Ms Shaw said Ava's temperature soared to 38 degrees and she was admitted to hospital.

On April 5, Ava had a full-body MRI at the Royal Children's Hospital in Melbourne and and two days later doctors gave her parents the devastating news - an aggressive form of cancer had spread throughout her body.

Ava had a tumour the size of the liver squashing her kidney, along with several other tumours in the bones, which resulted in the cancer infecting her bone marrow, blood and lymphatic system.

The deadly disease had even spread in her skull bones and eye sockets.

On April 5, Ava had a full-body MRI at the Royal Children's Hospital in Melbourne and and two days later doctors gave her parents the devastating news

She had a tumour the size of the liver squashing her kidney, along with several other tumours in the bones

Neuroblastoma Common solid tumour of childhood occurring between the ages of 0-5 years

A solid tumour arising from particular nerve cells, which run up the abdomen and chest and into the skull

The most common site for the tumour to grow is in the abdomen

About 50% start in the adrenal gland above the kidney

Neuroblastoma is a rare disease with about 40 children diagnosed each year in Australia

There is a chance of 1 in 100,000 of a child suffering neuroblastoma Advertisement

A GoFundMe page has launched to help the family raise $350,000 for treatment in New York.

Ava has undergone multiple surgeries and has had her ovaries removed and harvested.

Ava will not enter remission for another 14-18 months.

Ms Shaw said she is doing everything to make sure her daughter sees her fifth birthday.

'You'll do anything to make sure a child has the best chance at life,' she told Seven News this weekend.

'We couldn't sit back if this is her only chance of surviving.'

Ava has already had multiple surgeries and won't enter remission for another 14-18 months