The spectacular mass start, from the bucket of a digger, was watched by dozens of children and their parents.
As the plastic ducks bobbed their way towards Lake Wanaka, spectators and photographers ran alongside urging them on.
A tail-end Charlie with a stick and gumboots waded after the duck pack ensuring none were left behind.
Downstream, scores of spectators gathering around the finish line began to notice a duck and her ducklings nonchalantly sunning themselves on the bank.
When the first plastic ducks arrived, the live ducks stood up, peered at them for a moment and then plunged in to join the race for the last furlong to the lake.
After crossing the line, now surrounded by people and being gently bumped by plastic toys, the adult duck suddenly lost a little of her cool and fled with her brood out into the lake - no harm done.
The winning plastic duck, worth $500, was No 1318.
It is the third year Rotary has used the plastic ducks as a fundraiser during Wanakafest - "selling" them for $5 each.
Past-president Tony Brown said Rotary clubs all around the world used plastic duck races as fundraisers, and in Wanaka's case the money would be spent on community facilities.
Other Wanakafest events on Saturday were affected by strong winds, but the weather cleared yesterday.