While many Australians are aware of the importance of organ donation, it was donated skin that helped save Ms Pitt's life after she was horrifically burnt in 2011.

Ms Pitt was caught in a bushfire during the Racing the Planet Kimberley Ultramarathon, suffering burns to 65 per cent of her body. She lost the fingers on her right hand and two on her left hand.

Ms Pitt said doctors faced a race against time after initially trying to use the artificial skin product Integra to cover her wounds.

''Unfortunately, in my case, the Integra didn't work so they had to get skin from America,'' she said. But import restrictions meant doctors had to battle to ensure the tissue would quickly clear customs and quarantine.

''My doctor just said to them, 'listen mate if you don't let the skin through she will die','' Ms Pitt said. The former model and engineer, who lives in Ulladulla, participated in the annual Donate Life walk around Lake Burley Griffin on Wednesday to help raise awareness of organ and tissue donation.

Ms Pitt is not able to work while she focuses on rehabilitation. She will require several operations over the next decade.

She urged people to let their families know if they would be willing to donate organs and/or tissue.

Gift of Life president David O'Leary called the walk an amazing success, attracting more than 3000 people and eclipsing last year's number, despite the threat of rain.

''Going into the walk this morning to begin preparations it was raining pretty hard, and I had thoughts the numbers would dwindle compared with last year,'' he said.

''But fortunately the weather improved around the time of the walk,'' he said.

According to ACT Chief Minister Katy Gallagher, last year 30 Canberrans received life-saving organ transplants and 12 people donated organs.

Another 66 people received eye-tissue donations.

She urged Canberrans to let loved ones know of their decision to become organ donors.

''Experience to date shows that, if you want to become an organ and tissue donor, it's important to let your family know so that they can honour your decision if the situation arises,'' she said.

DonateLife Week runs until Sunday. For more information go to donatelife.gov.au.