Malaysia is not a signatory to the 1951 Refugee Convention and do not differentiate between refugees and other migrants.
Although Kuala Lumpur tolerates refugees and asylum seekers, including over 45,300 Chins, registered with the UNHCR but many still end up in detention camps.
Datuk Sakib Kusmi, the newly appointed immigration director general, said as of Saturday, 971 undocumented foreigners were detained in operations launched nationwide.
He said those detained including migrants without documents, workers who are overstaying, and those who own unrecognized documents.
Malaysia has just launched a 'whitening' scheme to legalize millions of undocumented migrant workers.
While urging employers and workers to join the scheme, termed officially as 'rehiring program', the government has warned stern action against those who employ undocumented foreigners.
Under the rehiring program, employers are expected to pay around RM4,000 (US$952) to legalize every undocumented foreign worker they have hired.
Last Thursday, Malaysia has also signed a memorandum of understanding (MoU) with Bangladesh to bring in up to 1.5 million new foreign workers to the country.
Before that, the government was criticized by different industry players and worker's rights groups after the announcement to increase levy for foreign workers. Under the new rates, the Malaysian government has planned to double the levy for migrant workers.
If implemented, the restructured levy rate for foreign workers is expected to bring in an extra income of RM2.5 billion (US$595 millions) to Malaysia, a petroleum exporter which is hard-hit by the plunging global oil price.
The government, however, has postponed the levy plan after widespread condemnation from employers and politicians. - Reporting by Thomas Chong