Australia said on Saturday it was investigating reports that three of its citizens were among a number of Crown Resorts employees that had been detained in China.

Australian consular staff have contacted Chinese authorities to confirm if Australian employees of the global gambling conglomerate are being held.

"The Australian Government is aware of reports of the possible detention of a number of Crown International Group employees across China, including three Australians," the Department of Foreign Affairs and Trade said in a statement.

A Crown Resorts spokeswoman said the company believed a number of its employees in China were being questioned by local authorities.

At least 18 employees from the group's sales and marketing team, including one senior executive, were rounded up, the Australian Financial Review has reported.

It is unclear why the staff may have been detained or if any charges have been laid.

Crown, part owned by Australian billionaire James Packer, has substantial interests in the Chinese gambling hub of Macau.

The company operates a joint venture with Macau-based Melco International Development, through which it owns and operates a number of gaming and entertainment resorts.

The former Portuguese colony is the only place in China where casino gambling is legal and has been hit by Beijing's anti-corruption campaign targeting officials and politically-linked businessmen.