More than 600 people braved the wind and drizzle at Peter Depena Reserve for celebrations beginning with a welcome to country by the Koomurri Australia group and an official flag-raising ceremony.
That was followed by a citizenship ceremony and the Rockdale Australia Day awards.
The longest line at the celebrations was for the sausage sizzle.
Annie Weinert and Michael White were among hundreds lining up for a sausage, something they do every year.
‘‘We’ve come every year for the past 20 years,’’ Ms Weinert said.
‘‘It’s always inspirational. We considered going into the city this year but Rockdale really is the best place.’’