A young boy who struggled with an auto-immune disease for most of his life passed away on Saturday.

Thomas Collins was just 3 years old when he died after being diagnosed with Severe Combined Immunodeficiency (SCID) just days after he was born.

The deficiency means he has no ability to fight off diseases and makes the risk of infections life-threatening.

He spent 858 days in the hospital and was kept in a "plastic bubble" to stop him from catching diseases.

Tom's conditions worsened while in a Melbourne hospital and the young family weren't able to move back to Queensland for support from their other family members due to COVID-19 restrictions.

Tom's parents Leah and Morgan Collins have been fighting for their son to be let into Brisbane as he was nearing the end of his days but were unable to get a response from Queensland Health in time.

The reason the family were in Melbourne was due to a specialist in a Melbourne hospital being the only person who could deliver the treatment Tom needed.

The family shared their heartbreak on Facebook.

“It is with deepest sorrow and fractured hearts that we tell you of Thomas’s passing this evening,” the Collins family posted on Facebook.

“He passed peacefully in the arms of his parents.

“Despite our best efforts we were unable to get him home to Queensland.

“No response from Qld was received in time. We understood the potential conditions were very distressing and would have separated our family during transport.

“We would then be forced to quarantine in the room he would have passed in as he was unlikely to survive 14 days quarantine.

“We chose to do what our son needed most, which was to be with his parents in a peaceful environment to the end. We were able to do that for him.”

“Sadly, we now have a choice between 14-day hotel quarantine, or wait 14 days south of the border to get back to Queensland, via NSW,” they said.

“We wished we could be surrounded by family during this time but this is the hand we have been dealt.”