Gladiator star Crowe is an old friend of Kidman's
Kidman, who is embroiled in divorce proceedings with Tom Cruise, and Crowe have denied reports that they were romantically involved earlier this year, when her marriage to Cruise failed.
Kidman is reported to have arrived at the Wakaya Club with her two children Isabella and Connor last week.
Crowe arrived there on Tuesday - though was accompanied by a female companion, said the bureau.
Crowe is now reported to have left the resort.
Privacy
The $1,300 (£900) a night Wakaya Club off the northeast coast of Fiji's main island Viti Levu is a favourite for the rich and famous, with Bill Gates honeymooning there and actor Pierce Brosnan a regular visitor.
The resort's management has denied reports that Kidman and Rose were there together, though is well-known for protecting the privacy of celebrities with such denials.
"They were not here - we have not had someone of that description staying here," resort manager Salesi Finau told the Reuters news agency.
Kidman and Crowe, who was born in New Zealand but grew up in Australia, have been friends for years, emerging from the small Australian acting community at the same time.
Mansion
Kidman and Tom Cruise announced their separation earlier this year after 10 years of marriage and after adopting two children, Isabella, eight, and Connor, six.
The glamorous couple lived in a sprawling harbour mansion in Sydney last year while filming separate projects.
Cruise won the hearts of sports-crazy Sydney residents by supporting a local rugby league team - and was seen at matches with Crowe, draped in the team's colors.