Crown Resorts has been unable to contact a number of it employees in China, after being made aware they were taken away for questioning and detained three days ago.
The 18 employees of Crown Resorts detained in China face between three and ten years in jail if charged with promoting gambling on the mainland.
Casinos are not legally allowed to advertise in mainland China, but operators have skirted around the issue by promoting resorts where casinos are located.
Beijing launched a highly publicised crackdown in February last year, through the Public Security Bureau. Hua Jingfeng, a deputy director at China's Ministry of Public Security, said it would focus on casino operators from neighbouring countries that had set up offices on the mainland.
The most senior of the Crown employees detained is Jason O'Connor, the head of VIP International for Crown who was in China on business last week.
It is believed Crown's Chinese marketing team was arrested in a series of raids in four cities across China on Thursday evening and Friday morning.
In a statement on Sunday, a Crown spokesperson said: "Crown believes that Jason O'Connor, the head of Crown's VIP International team is one of 18 Crown employees being questioned by Chinese authorities. To date, Crown has not been able to speak with our employees and is working closely with DFAT to urgently make contact and ascertain their welfare.”
The ASX-listed Crown operates casinos in Melbourne and Perth and is on-track to open a third casino in Sydney as a high rollers’ venue in 2020.
Under Chinese law, organising more than ten people to gamble overseas is considered illegal.
In June last year 13 Korean casino staff and 34 local employees from five venues based on Jeju Island were arrested on the same issue in a similar raid to the ones believed to have resulted in the Crown employees’ arrests.
Under the consular agreement between Australia and China, Beijing has 72 hours to inform Canberra if they are holding one of its nationals in custody.
A Department of Foreign Affairs and Trade spokesman commented: "The Australian Government is aware of reports of the possible detention of a number of Crown International Group employees across China, including three Australians."