Celebrity photographer Willem Pieterson told police Urban punched and kicked his car after he took pictures of him and Kidman walking to their car on July 27, Radar Online reports.
Pieterson claimed Urban drove up to his vehicle in the wrong lane before getting out and yelling at him, according to the reports.
He alleged the singer banged on the car window, hit the car with his fist and kicked the rear passenger door.
A spokesman for Metro Nashville Police Department, Don Aaron, said police could not see any damage on the paparazzo's car door and the incident had been classed as "intimidation".
Police are still investigating the incident.
Kidman, now 43, announced earlier this year that she had a second daughter, this time born to a surrogate. She has adopted two children with former husband, Tom Cruise, Isabella and Connor, who live with their father by their choice.
Kidman and Urban - who married in the Sydney suburb of Manly in 2006 - named their second baby Faith Margaret Kidman Urban. She was born on December 28 at the Centennial Medical Centre in Nashville, Tennessee, where the couple had booked out the entire top floor of the hospital.
After Kidman gave birth to Sunday Rose in July 2008, the couple tried to conceive again naturally, but failed.
They tried again through in-vitro fertilization (IVF), but were not successful. The couple were then advised by doctors to use a surrogate instead.
Kidman credited her first daughter's unexpected appearance to her swimming in the waters of a small Australian outback town during the filming of Australia.
She and six other women became pregnant after swimming in Kununurra.
Kidman's successful films include Cold Mountain (2003), The Interpreter (2005), Happy Feet (2006), and Australia (2008). Her performance in 2010's Rabbit Hole , for which she was also producer, landed her with an Academy Award nomination for Best Actress.