The father of a two-year-old boy fighting neuroblastoma has revealed how heartbreakingly difficult it has been to raise funds to save his son, while Israel Folau surges past their donation total to pay for his legal stoush with Rubgy Australia.

Andrea and his wife Jelena Magić are $200,000 shy of reaching their $350,000 goal to send their son Marko to New York for an experimental trial to try and save him from a rare type of cancer he started fighting in April last year.

Folau is asking for $3 million for his contract dispute and has already raised more than $500,000.

Marko was diagnosed with a rare type of cancer in April 2018. (GoFundMe)

After surgery and a brief glimmer of remission, multiple tumours have formed in Marko's pelvis, legs and potentially his spine. This has not only caused him pain, it restricts his movement and he now struggles to walk with a limp.

The rare cancer has also penetrated his kidney and with the best treatment available in Australia he would only have a 40-50 per cent chance of surviving to his seventh birthday.

The Melbourne couple are fundraising on GoFundMe, the same platform former Wallabies star Israel Folau managed to supersede their target in mere hours.

Marko's parents are trying to raise the money to have him included in a trial in New York that could save his life. (GoFundMe)

Folau asked for the public to bankroll his legal battle with Rugby Australia after his multi-million dollar contract was terminated over his comments condemning "sinners" – including the LGBT community – to hell.

Mr Magić told Today his family couldn't afford Marko's treatment if they sold everything they owned, and has lamented how challenging it has been to raise the money for a "forgotten cancer".

"GoFundMe was a place where we can reach a lot of people, common folk don't have that much publicity," he said from Melbourne.

"That was our only chance to give Marko a chance for life … to give him the best possible treatment that we as parents can give."

Marko had surgery to remove the initial tumour but several others have returned. (GoFundMe)

Israel Folau has been slammed for his funding campaign for his legal battle against Rugby Australia.

Folau has spent years playing professional sport. He's driven a Lamborghini, had lucrative contracts and sponsorships, sparking criticism that he is not in a position to be asking for money, particularly when others are in the fight of their lives.

“YOU are in a fight that YOU chose to be in after YOU broke the terms of YOUR contract, the kids below are in a fight they NEVER wanted to be in & yet YOU think YOU deserve donations more than they do??!!,” Wallabies legend Drew Mitchell posted on Twitter yesterday.

“It’s no longer about religion, it’s about YOU and YOUR greed."

If Marko had the best possible treatment in Australia he would still only have a 40-50 per cent chance of surviving the next five years. (GoFundMe)

Mitchell linked his comments to the accounts of other children like Marko fighting neuroblastoma.

Mr Magić said the crowdfunding campaign is also an amazing way to raise awareness for rare diseases and the families who are fighting to beat them.

"These strangers donating is not only saving Marko's life but this family and our lives."

He has pledged to donate any extra money donated that isn't required for Marko's treatment, or ensuring his wife and son have a roof over their heads in New York during the trial as he works looks after his two elder sons in Melbourne, to other charities and families in need.