The 46-year-old Hollywood actress was among the guests at the bash, along with her country singer husband Keith Urban, to celebrate Anthony and Janelle Kidman's golden anniversary, reported Contactmusic.
The party took place at the city's Middle Harbour Yacht Club.
Kidman was dressed in a green and ivory, flower-festooned dress and neutral pumps for the occasion, and as a festive touch added pale blooms on either side of her head.
Her daughter Faith sparkled in a silver sequin frock and clutched a cute panda bear mask.