The Immigration Department on Thursday said it had smashed a cross-boundary syndicate involved in forgery and the hiring of illegal workers.

The department also said a record 102 people had been arrested as part of the operation.

It said the syndicate had been actively recruiting mainland residents through online communication groups, luring them to work illegally in Hong Kong.

Officers said once the recruits arrived in the SAR, the syndicate provided forged Hong Kong identity cards, arranged dormitories, and assisted with job seeking.

The department said the syndicate profited by charging mainlanders for the forged IDs, collecting rent from the arranged accommodation, and taking a cut from their salaries.

After about one year of operation, the syndicate is estimated to have earned more than HK$20 million — the highest amount recorded when compared with similar cases.

The department launched a joint-operation with mainland law enforcement bodies between October and January, nabbing 119 people across both sides of the boundary.

During raids at multiple locations across Hong Kong, including at suspected dormitories and workplaces employing the illegal workers, 102 people aged between 32 and 74 were arrested.

Among those arrested were two individuals believed to be the masterminds and core members of the syndicate, 83 suspected illegal workers, and 17 employers who allegedly hired them.

Senior Principal Immigration Officer Tang Ka-fai said the syndicate had hidden the forged identity cards well, making detection difficult for enforcement officers.

“When they raided the hideout of the illegal workers, some of the forged Hong Kong identity cards were hidden in some very hidden places, for example, inside books or some cans,” he said.

“Our investigators spent quite a lot of time taking out all the forged Hong Kong identity cards in the hideout.”

He said the forged ID cards seized were of inferior quality and lack security features.

The officer added that, with careful observation, employers should be able to easily tell the difference between real and forged ID cards.