Devi Asmarani, Jakarta – The urban centres of Batam, Java and Sumatra will be swamped by at least 100,000 workers returning from Malaysia this week – and they won't be welcome.

Already beset by problems coping with migrating workers from other parts of Indonesia, several Indonesian provinces will be hard pressed to cater to a whole new batch and officials are already fearing massive social unrest.

Provincial officials in Sumatra have even threatened not to allow ships ferrying these workers to dock.

They also complained of Jakarta's lack of help and funding in anticipating the influx of illegal workers to be deported by the Malaysian government, citing they were already saddled with various social problems.

North Sumatra, Batam and the East and West Kalimantan are the likely entry points of the workers, who number around 400,000.

They are in a rush to leave Malaysia before the enactment of a harsh new immigration law comes into force on Thursday.

There are also those waiting to head over to Batam or Bintan in order to return to Java.

Ferry services to Java run twice a week from these two ferry terminals.

Jakarta has said that it would deploy several Navy ships to transport the workers back to their respective homes, but so far only two ships had been deployed to carry some of the workers from East Kalimantan back to Sulawesi.

North Sumatra, which is a four-hour ferry trip from the Malaysian peninsula, is even planning to ban the workers from entering the province, at least until Jakarta guarantees to finance their accommodation and provide their transport immediately back home.

Spokesman Eddy Sofyan for North Sumatra provincial administration told The Straits Times: "We want them to stay offshore until we know for sure what the central government is doing with them, who is providing their accommodation and when they are going to be sent home." He said the administration had learnt from experience. Earlier this month, some 700 workers rallied in front of the Governor's building soon after they arrived from Malaysia.

They were then given shelter by the local administration and eventually left after a local businessman paid for their trip to Java, he said.

North Sumatra is already burdened by some 122,000 refugees from the neighbouring province of Aceh, where separatists are fighting Indonesian troops. Like Sumatra, Batam is also another port of disembarkation for these workers.

The commercial hub is also already hard-pressed with the rising number of migrant workers from other parts of Indonesia, causing high unemployment and crime levels.

Some border areas are already swamped by the returning workers. In Nunukan, a small island off of East Kalimantan, over 10,000 workers have returned from Malaysia.

Local authorities said some 2,000 workers arrive from Malaysia everyday. It is now facing a water shortage because of the influx.

Former Manpower Minister Bomer Pasaribu said the Indonesian government had been slow to anticipate the inevitable deportation of its workers from Malaysia.

He told The Straits Times: "There could be up to one million Indonesian workers in Malaysia, 85 per cent of them are illegal. 'Imagine if these people return home, it is a recipe for social unrest and will surely boost crime levels."