Jones dramatically quit the Socceroos 2010 World Cup squad in June last year after his five-year-old son Luca was diagnosed with cancer.

The family hoped Luca would be cured after he had a stem-cell transplant last September but recent tests have revealed that acute myeloid leukemia has re-appeared.

Luca now needs another transplant which is reliant on finding matching bone marrow stem cells or blood and Perth-born Jones urged people to register to donate.

"It's about getting people on the register and the fact that so many people need transplants and there's not enough donors obviously we're trying to spread the word," Jones told The Sunday Times.

Jones added: "Luca's disappointed that he's back in hospital. He only spent five weeks at home before he went back.

"He doesn't understand the full story, but he's been really good because he knows what to expect and he's seen the same people.

"The doctors always tell you there is a chance it will come back. We hoped that it wouldn't, but unfortunately it has.

"They say that some people have three transplants and survive, so it's not the end of the world, but it is a big dent in his recovery."

Jones continued: "The doctors are really happy with how he's reacted to the medicine so far, but it's still wait-and-see on how he will go in the longer term.

"Last time he was in from June to November, so we assume it will be very similar. We're probably looking at the best part of five months, anything less is a bonus."