Malaysian authorities have called up 300,000 volunteer reservists to help in arresting those who choose to stay behind as part of the biggest round-up campaign since 2002 to end the problem of illegal workers.
According to Malaysian officials, about 400,000 illegal foreigners have already left the country, while at least 200,000 others still remain.
Those who fail to capitalise on the government's amnesty to leave will face punishment of fines, imprisonment and even whipping before getting deported and permanently barred from entering the country.
Thousands of illegal Indonesian workers have been rushing to leave the country to avoid the government's widespread crackdown.
"I feel sad leaving, but I don't want to be whipped or jailed. I will definitely come back legally. There is not much work back home," Muhammad Sifud, 30, who has worked illegally in construction for 10 years, said.
Many Indonesians are drawn to
Malaysia where jobs are plenty
Many other illegal workers, however, were planning to remain in the country, claiming they had no other alternative.
"People ask me many times am I not afraid of being caught and jailed?" Alia Shukri, from a remote village near Bali, said.
"Yes, I am scared, but what choice do I have? I have three children and there is no chance to earn a decent income to support them if I return home," he added.
In a bid to encourage illegal aliens to leave before the amnesty ends, the government has also offered the chance for a legal return to Malaysia and has agreed with the Indonesian government to speed up the procedures to allow them back with proper papers.
Malaysian Home Affairs Minister Azmi Khalid has said illegal workers who leave voluntarily can return to their jobs in Malaysia almost immediately.
Malaysia's prosperity is the envy
of many poorer neighbours
They can get their work papers and come back within 24 hours under fast-track procedures adopted by the ministry.
Kuala Lumpur says it has already delayed the crackdown three times at Indonesia's request, but will not extend the amnesty further.
Malaysia has a severe labour shortage and relies mainly on low-wage workers from Indonesia.
Many employers fear the crackdown will exacerbate the shortage.