The Oscar winner flew into Sydney on Tuesday, the Seven Network reported. Kidman was carrying baby Faith Margaret, six months, and holding hands with elder daughter Sunday Rose, two, as she left the airport.
She was due to head to the city's north to spend time with her family, including sister Antonia who now lives in Singapore with her second husband Craig Marran and her five children, including the couple's baby son Nicholas.
Kidman turned 44 last week. Faith Margaret was born on December 28 in Nashville, Tennessee, through a surrogate mother and is the biological child of Kidman and husband Keith Urban. Kidman said in January she planned to take six months off to concentrate on "all things related to the family". Kidman also has two adopted teenage children, Isabella and Connor, with ex-husband Tom Cruise.