Mr Gribilas, 31, had a successful transplant operation at the Onasseio Hospital in Athens last weekend.

The hospital, considered to be among the top medical facilities in Greece, has declined all requests to reveal his identity. But the Herald understands Mr Gribilas was born in Australia, where he lived as a child before moving to Greece with his parents, later meeting his Greek-Australian partner, Poppy, who he married last month.

Mr Zammit's father, Oliver, has appealed directly to authorities to improve health care on the Greek islands.

He met with the Health Minister, Dimitris Avramopoulos, before flying back to Australia and suggested that Greece should do more to care for tourists.

"You have thousands of people going to these islands and these tourists need to know that if they get into trouble, they can get the medical care," Mr Zammit said.

"It's not always about money, it's about life."

Mr Zammit's son, Doujon, had to be flown to Athens for treatement after he was attacked on the island. His father decided to turn off his life-support machine last Friday and donate his son's heart, liver and kidneys.

Mr Avramopoulos revealed that the Zammit family's decision had already prompted others to follow their example.

Greece has one of the lowest donation rates in Europe of about six donors per million, but the minister said since Friday two other families had donated organs of their loved ones.

"As he leaves Greece, Mr Zammit is leaving behind siblings of his son," Mr Avramopoulos said, referring to the people whose lives were saved by the transplants.

Greek media has reported the names of two other recipients of Doujon Zammit's organs.

It is understood that Dimitra Pappa had a double kidney and liver transplant at Thessaloniki's Ippokratios Hospital, while Loukas Chatzimichail received a kidney at Evagelismos Hospital in Athens.

Greek media has also reported that three men bailed over the attack may face additional charges. A 25-year-old nightclub bouncer remains in custody.