More than one third of older Australians wrongly believe they are too old to donate, new research finds.

Research commissioned by the Organ and Tissue Authority has found that while 81 per cent of Australians aged 65 years or more are willing to become organ and tissue donors, more than one third wrongly assume they are too old to donate.

“Age is not a barrier to becoming an organ and tissue donor,” said the Parliamentary Secretary for Health and Ageing, Catherine King.

"My message to all older Australians is to please let your loved ones know your wishes about organ and tissue donation and to understand that age is not a barrier to saving or improving the lives of others.”

She said people who have had cancer or other health problems have been able to become a donor and she called for older Australians to advise their families about their wishes about organ and tissue donation

The research also found that half of people aged 65 years or over have not discussed their donation wishes with family members in the past 12 months and 28 per cent have never had the discussion.

"Many Australians aged 65 years or over believe that it is better to just leave it to their family to decide, even though 82 per cent of them believe it is important that their family know their wishes,” she said.

In 2011, 54 Australians aged 65 or over saved or improved lives by donating their organs including lungs, kidneys and livers. Older Australians also donated tissues including corneas which help to restore and improve the sight of others.

“While the median age of all organ donors last year was 50 years – there was a very broad age range with the oldest organ and tissue donor in 2011 being over 85 years," said King.

There are around three million Australians aged 65 years and above and this is a growing demographic.

"No one should ever assume that they are too old or unhealthy to become an organ and tissue donor. Transplant professionals will decide which organs and tissues can be used at the time of death after looking at your past medical history, the condition of your organs and their suitability."