The Duchess of Cornwall is attending an event with Osteoporosis Australia at Government House in Melbourne.
The duchess's mother and grandmother both died from the condition. AAP reports she has done a lot of work to raise awareness of the plight of sufferers over the past decade.
She said raising awareness of osteoporosis was a cause very close to her heart.
"I watched my mother die in agony from this disease," she said.
The duchess said it was important to bring the message worldwide that osteoporosis can be prevented.
AAP reports she was accompanied on Wednesday by Elizabeth Chernov, the wife of state governor Alex Chernov, and Robyn Baillieu, wife of Victorian Premier Ted Baillieu.
Prince Charles and Camilla are on a six-day Australian tour to mark the Queen's Diamond Jubilee.
The Prince of Wales attended a housing symposium in Melbourne on Wednesday.
He said Melbourne was renowned for its historic and contemporary architecture.
"You have done a tremendous job in preserving the past and creating well loved and well used urban spaces in the present day," he said.
"Unlike most cities around the world, Melbourne kept its tram system and improved it and is now considered a global leader."