Mr Brown's wife of seven years, Leanne Brown, took her own life in February last year and was a registered organ donor.

The Organ and Tissue Authority is calling on Australians to sign up to the scheme on the back of a new survey.

The poll, released on Sunday, shows there is huge support for organ donation but only one-third of Australians are signed up.

Despite the traumatic experience of Mrs Brown's death, Mr Brown said organ donation added another chapter to her life.

"In the last month my little girl has asked me where her mum is," he said.

"I'm able to say, 'Actually, the last time we saw your mum she was going off to save four lives'."

He received a letter from the daughter of one of the recipients, who told Mr Brown her mother was able to walk her down the aisle thanks to Mrs Brown.

"When I got that news I went for a run afterwards and I felt 10 feet tall and bulletproof," Mr Brown said.

"This has given us something that I will hold on to really tightly."

The couple signed up to organ donation five years into their relationship after they were told a family friend needed a new heart.

Australians overwhelmingly believe in the benefits of organ donation and of those not registered as donors, only one in five are unwilling to sign up.

Survey respondents said often families didn't allow their loved ones to be organ donors because they didn't know their wishes before they died.

In 2019, nine out of 10 families agreed to donation when their family member was a registered donor.

Australians aged 65 and over were the most likely to be registered, while younger Australians were the least likely, the survey found.

"It's not something that's easy to discuss around the dinner table," Mr Brown said.

"We live in such a good country with such an amazing health system. Mortality is not something we typically plan on confronting for a really long time."

Organ and Tissue Authority chief executive Lucinda Barry says it takes less than a minute for people to sign up online and they only need a Medicare card.

"Tell your family and take that next step to register," she said.

"There will always be people who need a transplant. We will never meet the demand. It means they really are getting a second chance at life."

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Australian Associated Press