Ellis, 47, qualified to compete in the Ironman World Championship 70.3 in Las Vegas in September with victory in a half-ironman contest in Canberra on Sunday.

The mother of five overcame a hamstring complaint to win the female 45-49 category at the Canberra 70.3 ironman.

The 70.3 ironman series sees competitors complete a half-ironman consisting of a 1.9-kilometre swim leg, 90.1-kilometre bike leg and a 21.1-kilometre run.

Ellis said a hamstring problem hindered her training for the past three months.

"I haven't been able to do the speed work," she said. "I've recently run two half-marathons with my daughter, so I've been able to compete, just not as well as I'd like."

Ellis said after visiting numerous physiotherapists, it was Donald's Pat Allen who helped her.

"After my first visit to Pat my hamstring was feeling much better. That was only two weeks ago and then I saw him again the day before I got on the plane," she said.

"He told me I'd be able to go as fast as I wanted and he was right."

Ellis said her hamstring felt fine as she claimed victory. She said it was the Canberra weather which presented the biggest challenge.

"As soon as we got on the bikes it started bucketing down with rain," she said.

"It was a very hilly course too, so it was tough," Ellis said.

"By the time I was off the bike the rain had subsided and the sun was out, so then it came out hot and steamy.

"Not long after I finished, it started pouring rain again."

Ellis finished the swim leg in ninth place before moving to the front of the field in the bike leg.

She then held on to the position during the run leg to win her category with a time of five hours, nine minutes and 33 seconds.

The result placed her in the top 20 females across all categories.

Ellis said she was excited about competing in the World Championships.

Next year will be a big year for Ellis, who is also planning to compete in a half-ironman contest in France in June.

"I can't wait to get into the training," she said.