The Australian actress, 52, made a brief appearance at a pre-Golden Globes event in Los Angeles on Saturday (US time), looking visibly upset.
Kidman's representative told Us Magazine that the couple are "keeping a close eye" on their rural property, which is "under threat" from the NSW wildfires.
The Oscar winner refused red carpet interviews, saying she was "so distracted".
"I'm so sorry. I'm so distracted right now with everything that's happening in Australia," she apologised, according to attendees.