The 47-year-old made the difficult decision to sell his Atlanta 1996 Olympic medal, which he won for trap shooting, after being confronted by news he needed a heart transplant and gall bladder surgery.

Diamond had already auctioned his second gold medal, won for the same event at the Sydney 2000 Olympics Games, for $72,000 in 2017.

He followed the auction of his remaining medal - which was expected to fetch up to $70,000 - from hospital, where he is recovering from gall bladder surgery he underwent on Tuesday.

It went for $50,000, which will be used to support his three daughters with ex-wife Cathy.

Diamond's dreams of competing at a seventh Olympics and possibly picking up another medal in Tokyo next year were dashed when he was rushed to a Newcastle hospital with heart failure about a month ago.

With a heart functioning at only 15 per cent, Diamond's goal now is to be around to worry about his kids.

"It's a pretty sobering feeling to have your heart fail on you," Diamond told New Idea in November.

"I do want to hang around - I want to see my kids get older and get married and I want to have grandchildren."

Australian Associated Press