The exchange student from North Carolina was one of nearly 1000 participants in Sunday's Variety Santa Fun Run, a five-kilometre charity race in support of Variety children's charities. Runners, riders, and even a couple of pets took to the track around Lake Burley Griffin, some donning their outfits as the race took off.

Ms Gardner was the first Ms Claus across the line, a tie-dye bandanna attached to her Santa hat.

"Usually I've got my tie-dye on but not a Santa suit," she said. ''I'd seen the centenary website and thought this would be fun. I love running in fun runs more than competitive ones because everyone's smiling and it's such a great atmosphere."

The fun run's ambassador is five- time Paralympian and Canberra local Richard Nicholson, and run organiser Jill Hart said that 980 people had registered for the Canberra event this year.

Sunday's event was the first time it had been held at the same time in capital cities around the country. "It was the biggest year we've had … there were a few surprised spectators," Mrs Hart said.

"It's one thing to see a fun run, it's another to see 1000 people running in Santa suits.

"It was just hilarious."