Three Australians are in the group detained late last week, including Crown's head of international VIP gambling Jason O'Connor, in what the industry fears could be a crackdown by Beijing on the promotion of offshore gaming by international companies.
"I am deeply concerned for the welfare of those Crown employees detained in China," Packer, who owns 53 percent of the Australian-listed company, said in a statement. "I am respectful that these detentions have occurred in another country and are therefore subject to their sovereign rules and investigative processes."
China's Foreign Ministry said at its daily press conference on Monday that the Australians were "detained by the Shanghai police under gambling charges on October 14." The nationalities of the other detained staff have not been made public.
Casinos cannot advertise in China and promoting gambling in other ways, such as advertising resort facilities or offering credit to high-spending clients, can also be problematic.
Thirteen South Korean casino managers were arrested in China last year for offering Chinese gamblers free tours, free hotels and sexual services.