Two Indonesian men and two women were arrested in the first operation at the Terminal Bersepadu Gombak.
Another Indonesian man believed to be acting as a “transporter” responsible for managing the migrants’ movement and logistics around Kuala Lumpur was also detained.
Three Indonesian men and three women believed to be linked to the same syndicate were also arrested at the Terminal Bersepadu Selatan (TBS), the department said in a statement.
Preliminary investigations found that the syndicate had shifted from using sea routes in Selangor waters to a more complex, layered approach involving both air and land routes to mislead authorities.
The syndicate also avoided direct flights to Malaysia because many of the migrants involved were believed to have been blacklisted from entering the country.
Among the identified routes was the movement of migrants from Indonesia to Singapore as a transit point before being flown to Hatyai, Thailand. Kuala Lumpur International Airport (KLIA) was also identified as a transit point before flights to Hatyai.
Upon arrival in Hatyai, the migrants were placed in transit houses before their entry into Kelantan was arranged through illegal routes along the Thailand-Malaysia border in Bukit Bunga, Tanah Merah.
After successfully crossing into Bukit Bunga, the migrants were then transported to Kuala Lumpur using express bus services from various companies on the same day, typically travelling at night.
The syndicate, believed to be headed by a mastermind based in Indonesia, operated through a network of intermediary agents working separately in Hatyai
Each agent had a specific role, including managing migrant arrivals, providing transit accommodation, and falsifying passport entry stamps to deceive authorities.
The network operated in a layered structure with specialised roles to break the flow of information between migrants and syndicate members, making detection more difficult.
Those arrested, aged between 27 and 60, were believed to have paid between RM3,500 and RM4,000 each to the syndicate to arrange their illegal entry into Malaysia.
The immigration department said it was working to track down local residents believed to have colluded with the syndicate by purchasing their bus tickets and coordinating travel logistics.
The detainees are being investigated under the Anti-Trafficking in Persons and Anti-Smuggling of Migrants Act 2007 and the Immigration Act 1959/63.