Its director-general Mustafar Ali said the department would further intensify the operation to detain illegal immigrants from the date.

Employers who hired and harboured illegal foreign workers would also be detained, he said.

“We have started the voluntary surrender programme, better known as 3+1, which enables all illegal immigrants in the country to return to their countries of origin voluntarily.

“So they still have until Aug 30 to surrender before we take a more firm approach,” he told reporters after participating in Op Mega at two construction sites at Jalan Gambang here yesterday.

He said so far, more than 3,000 illegal immigrants had been arrested nationwide for various offences in Op Mega which was launched on July 1.