Plucka Duck and Nullica Duck stood up river with their spawn of rubber quacking competitors, before launching them off the bridge with a splash in the inaugural "Nullica Duck Race".

Canoes, nets and a multitude of hands stood waiting at the finish line ready to collect the winner and the other 499 before they went out to sea, kids even stuffed them in their shirts as a way to hold them.

Joanne Korner from Imagine EDEN, a community-focused non-profit group, said the Nullica River Duck Race was established as something for children to enjoy while also raising funds for groups they supported.

"We tested the ducks out a couple of days earlier and they went down really well, and then we went out the next morning and there was that much water going down, we thought, 'Oh no'," Ms Korner said.

"But by the time it was low tide it sort of settled down a bit, the sun came out and it was beautiful."

Those who attended had the opportunity to enjoy a free barbecue where 200 sausages sizzled, and prizes were awarded for best sandcastle and best driftwood Yowie huts.

Using washed up pieces of wood from across the beach, groups built wooden shelters, some appeared like bonfires with tree remnants leaning together, while others used seaweed for roofs.

"They did a good job, and the kids had little seats, fires, gardens, and fences, so they all went out [with designs]," Ms Korner said.

First prize in the Duck Race was $1000, second prize was a Great Southern Trike Tour, children with the best sandcastle received $30, and best Yowie hut won a family pass to The Picture Show Man in Merimbula.

"We are donating [the money] to the Eden RSL Memorial Hall because they get on board with a lot of stuff for us," she said.