A further 12 per cent of people aged 18-29 years surveyed by Galaxy research believed that sharing knives, cups and other household items was a high risk.
While 53 per cent thought HIV was transmissible from blood transfusion.
"For people aged over 30 who remember the early HIV awareness campaigns which dispelled many myths, these misconceptions will be seen as quite alarming," News.com.au quoted Dr Roger Garsia, Chair of the NSW Ministerial Advisory Committee on HIV and STIs, as saying.
Gary Taylor, 32, was diagnosed with HIV three years ago. He said the misconceptions of younger people and in particular his family made him feel "dirty."
"A lot of my family thought you could catch it from grabbing my fork, from kissing me or hugging me or using the toilet seat, until I found out I had HIV, I thought you could catch it that way too," Taylor said.
"It's really just like living with cancer, you can touch me, you can hug me, you can drink out of the same cup as me. You're not going to get HIV unless you have unprotected sex with me."
Most of the people the world over think that AIDS is an advanced state of HIV infection, and a disease that heterosexuals and children can acquire.
Taylor said: AIDS is not the same as HIV. HIV is a treatable disease. I will probably die from old age. AIDS is what you get if you have left HIV untreated.
"If you don't see HIV in your peer group, you think it's gone away and therefore you don't need to take any precautions. So people tend to have more unprotected sex," Taylor added. (AN)