What is the rational of not allowing withdrawal of CPF for West Malaysians?

What are the withdrawal policy for their Employee Provident Fund in Malaysia for foreigners working there including singaporean? If you are leaving for good and not return to work in our country I'll think they will be able to do so. Each day 20,000 or more leave malaysia into singapore to work legally and illegally that why the foreign worker levy is enforce to tackle this problem because west malaysia is easily link by road to our country. I think CPF Board will be able to give their view regarding their policy regarding these issuse