The Australian actress's arrival in Hong Kong has sparked widespread anger after she was reportedly spotted out and about two days after touching down.
This is despite the region having some of the strictest rules in place, with up to 21 days' quarantine required.
There has been no direct, official comment on a possible exemption.
However, Hong Kong's Commerce and Economic Development Bureau sent out a statement on Thursday in response to questions about "overseas film personnel" and quarantine, explaining restrictions are waived "to carry out designated professional work".
Kidman is in Hong Kong to film a new show about the lives of wealthy, glamorous ex-pats - already a source of tension as locals contend with increasing restrictions under the new national security law.
Reports of the waiver have only stoked outrage further, with comments on both Twitter and Chinese social media platform Sina Weibo overwhelmingly critical.
"Which department gave her the right?" one users asks. Another asks: "Who gave her the right to be exempt?"
Several people point out they have not been able to see family for months thanks to the restrictions.
Citizens living in "high risk" countries - a list which already includes the UK and is expanding to places like the US and Spain tomorrow - are only allowed to enter if vaccinated and must still complete three weeks' quarantine.
Australia - where Kidman flew in from - is classified "medium", which has a minimum seven-day quarantine requirement for those who are vaccinated.
"So we have HK residents who can't come back if not vaccinated (and even then with 2-3 weeks quarantine) but Nicole Kidman can just enter like this? It's disgusting!" a Twitter user called @WhovianBooknerd wrote.
"Why do foreigners have privileges?" one person asks on Weibo.
The anger has made its way off social media and into the political arena, with Elizabeth Quat, a pro-Beijing lawmaker, saying she had received "a number of complaints" and has asked health officials to explain themselves, according to AFP news agency.
The issue of film stars travelling internationally has also caused problems in Kidman's home country, Australia, where the arrival of a host of famous faces in the last 18 months has angered those struggling to get home.