A proposal to automatically make people organ donors could reduce the number of available organs, the authority in charge of the system says.

The idea of forcing people who do not want to donate their organs to opt out of the organ donor register is one of several aimed at combating an illegal international black-market trade that has some organs selling for hundreds of thousands of dollars each.

The idea was raised in the recommendations of a report to Parliament by the Joint Standing Committee on Foreign Affairs, Defence and Trade's Inquiry into Human Organ Trafficking and Organ Transplant Tourism.

However, the Australian Organ and Tissue Authority's national medical director, Helen Opdam, said an opt-out system could create confusion about the wishes of a person who had recently died and ultimately prevent their organs from being used.

"People say, well, if we had opt-out, everyone would just say 'yes'," Dr Opdam said.

"I don't think that would happen, actually.

"I think, in the absence of families knowing that their loved one wanted to be a donor, they may still just say 'no', even with the presumed consent law.

"We certainly see that in countries with presumed consent or opt-out laws."

Communicating wishes to family is vital

Regardless of whether a country's organ donation register was opt-in or opt-out, there tended to be a desire to divine the wishes of the recently deceased before giving their organs to another person, Dr Opdam said.

That meant an opt-in register provided more clarity than an opt-out system because people had to make a deliberate choice to become an organ donor.

However, communication of those wishes with family members remained vital.

Dr Opdam said in Australia, when a person had opted to go onto the donor register and had communicated that desire to their families, about 90 per cent of families agreed to donate the person's organs.

When a person had chosen to go on the register but failed to talk to their families before their death, that figure dropped to about 50 per cent.

Another factor was the small pool of people with useable organs to choose from.

Dr Opdam said only about 1,200 people a year died in hospital on a ventilator — circumstances that meant their organs could be donated.

"Of those, last year we had a little over 500 people become donors," she said.

New heart gives new life

Wade Eathorne pictured with his three children, Savannah (on his lap), Indiana (right), and Scarlett (back). ( Supplied: Wade Eathorne )

One person to have benefited from Australia's organ transplant program is Sunshine Coast man Wade Eathorne, who suffered a massive heart attack while at work at a bank in April 2016.

He was only 41 at the time.

"I felt hot and sweaty, then everything went black," Mr Eathorne said.

"There was no pain."

Mr Eathorne said he was told he had to be revived twice — once in the ambulance and once at Nambour Hospital — and when he awoke, he needed a new heart, an idea he initially rejected.

Wade Eathorne's wife Justine led the charge in the family's efforts to raise funds for organ donation research. ( Supplied: Wade Eathorne )

"I thought, 'This is no problem. I'll get over it. I have gotten over illness before. I'll be fine'," he said.

That thought was quickly ended once it became clear how badly his heart had been damaged.

"The valves had exploded and they'd separated too far," Mr Eathorne said.

"It couldn't be surgically repaired."

In the end, Mr Eathorne got lucky and a new heart was found for him in a matter of weeks, rather than the months he had been expecting.

These days Mr Eathorne goes to the gym four or five times a week and says he feels like a new man.

He and his wife Justine are now actively involved in fundraising to help other people in need of organ donations and to help fund research in organ donation.

Brisbane-based transplant specialist Dan Chambers said the efforts of people like the Eathornes and work by the Organ and Tissue Authority had helped triple the number of lung donations in Queensland over the past few years.