It was an item on the 31-year-old's bucket list that she would not have been able to tick off had it not been for the assistance of teammate and good friend Craig Gruber.

In Sunday's event, in the pouring rain, the Illawarra paramedic used a harness to pull Sharn's kayak in the 3.8-kilometre swim leg; he pushed her wheelchair on the 42.2-kilometre run and he attached her bike to his on the 180-kilometre cycle. It took almost 16½ hours - and a hell of a lot of courage from them both.

For Sharn, who was diagnosed with a rare, aggressive form of the debilitating neurological disease last July, it was a dream come true.

While the condition has caused extensive muscle wastage, affecting her balance and mobility, she managed to get out of her wheelchair and walk the last 100 metres to cross the finish line.

It was a proud moment for her husband, Russell, who was at the line to give Sharn and Craig their medals as a chorus of cheers erupted from her team of supporters - known as Sharnie's Army. Russell said it was one of the best days of his life.

"I was very proud four years ago when I married Sharn - on Sunday I was even more proud of her," he said. "She battled through the swim leg with strong swells, she didn't stop pedalling on the bike leg and she helped push her wheelchair for a good percentage of the leg run.

"Sharn and Craig did an amazing job in challenging conditions and came in just after midnight, 45 minutes before cut-off."

Russell said as well as the Illawarra supporters who travelled to Cairns for the big event, there was great support and encouragement from ironman management, participants and spectators.

"People were running out of restaurants and shops every time Sharn and Craig passed by," he said.

"There was about 250 people at the finish line specifically for them - it was an incredible day."