Liverpool was his first call.

Pat Pedraja looks like an average sport-loving 13-year-old but to a leukemia patient who needs a bone-marrow transplant he is a hero.

Pat, of Florida, started Driving for Donors last year, after he watched other young patients die while waiting for a transplant.

Pat and his family drove all around the US in his ``Donormobile'', enlisting 11,000 new donors.

His goal for the next two weeks is to register 2500 donors in his tour around Sydney and Melbourne.

``I want to keep inspiring people and get everyone to try and make a difference in their community,'' Pat said.

Pat won the CNN Heroes Viewers' Choice awards and his mother Claudine said he has become quite the celebrity.

On Monday, Pat met with 19-year-old Petra Velkovski, from Prestons, who was diagnosed with acute lymphoblastic leukaemia when she was 16.

``I think it's amazing what he's doing, he's an inspiration, we need more people like Patrick to raise awareness about donating,'' she said.

Ms Velkovski is now an ambassador for Cure Our Kids, helping others affected by cancer. Ms Velkovski, who comes from a Macedonian background, said it was important to enlist people with an ethnic background because Australia is very multicultural.

Clinical studies by the Australian Bone Marrow Donor Registry have shown that patients do better with younger donors and patients are more likely to find a match within their own ethnic group.

Sally Gordon, ,the registry's executive director, said around 10,000 Australians were diagnosed each year with leukemia or other blood disorders.

About 70 per cent of people who need a bone-marrow transplant won't find a match within their own family and must rely on the registry to find a matching donor.