Grey skies and some early drizzle did not deter hundreds of contestants and spectators who flocked to the beachside town's annual sand modelling competition.

Broulee Mossy Point Community Association member Marie Zuvich said the contest had run for a decade and more than 100 teams registered on Wednesday.

Groups of locals and holiday-makers with names such as The Griswolds, The Itchy Bogs and Mystical Mermaids staked out their patch and began to shift sand as soon as the start whistle blew at 10.30am.

Guidelines stipulated contestants choose between a sculpture or sandcastle, and no external props were allowed.

But it's holiday time on the coast, and no-one's a stickler.

"No rules, have fun," Ms Zuvic told one entrant.

"It's jolly, it's jovial, anything goes."

Contestants had one hour to create their masterpieces, which ranged from turtles and mermaids, to blocks of chocolate and elaborate castles.

John Inglis, of Hackett, sunbaked on his towel to help his family recreate an iconic Australian image.

His son, Rick Inglis, said: "The inspiration is that Max Dupain photo, Sunbaker.

"Ours isn't as good, but that's the inspiration."

Close by, the Jackson family of Jerrabomberra fashioned a life raft like the one in Hollywood film Cast Away, complete with a Wilson-brand soccer ball and a mock FedEx package.

"We'll probably get disqualified because we've got external props, but we don't care," Kim Jackson said.

"As long as we give people a laugh."

Backyard cricket matches inspired Chapman's Tiana Martiniello, 14, and her cousins to sculpt stumps and a bat in tribute to fallen cricketer Phillip Hughes.

But it was a family group from Tuggeranong who took out top honours in the sculpture category for their skate ramp and injured skateboarder.

Amy Allpress, 23, said the idea came from a rushed team meeting the previous night, a few rough sketches and her dad's 1970s skateboard.

"We try to come up with a better idea each year," she said.

Competition crowds at the beach's northern end braved Wednesday's coastal cold snap.

Bureau of Meteorology senior meteorologist Peter Zmijewski said a southerly change had brought cooler temperatures that peaked at 21 degrees on Wednesday.

While some clouds were expected to stay around on New Year's Day, the mercury was tipped to rise to a top of 32 degrees.

Temperatures would hover around 30 degrees on Friday but reach 35 degrees on Saturday.