Kidman is back in Sydney to work on her new film

CCTV footage showed a man apparently planting the bug in the street near Kidman's Sydney home on Sunday.

The Oscar-winning actress is currently back in Sydney to film her latest movie, Eucalyptus, with Russell Crowe.

Police said they were keen to speak to paparazzi photographers who were seen staking out Kidman's home in the hope of securing a picture.

Work commitments

Detective inspector Grant Taylor said they had spoken to Kidman about the discovery.

He said: "Miss Kidman has been spoken to today at her house in relation to this matter, she is undoubtedly concerned in regards to why this device may have been placed there and if she is the potential target of this device.

"At the time this device was found there were media paparazzi, if I may use that term, in the street."

Police added that the listening device was commonly available in electronics stores and was being examined.

Meanwhile, Kidman has turned down an invitation to attend the presentation of the Australian of the Year award in Canberra on Tuesday.

The actress' publicist, Wendy Day, said Kidman's work commitments on Eucalyptus prevented her from attending.