2. Is Tax clearance needed for all non-citizen employees? Are there any exceptions?

YES, there are exceptions. Tax clearance is NOT required for:



a. Singapore Permanent Residents who are merely changing jobs in Singapore and are not leaving Singapore permanently.

You do not need to seek tax clearance for employees who are Singapore Permanent Residents who are merely changing jobs in Singapore and are not leaving Singapore permanently after they cease employment. The employer may obtain a Letter of Undertaking confirming his stay in Singapore for his record.


http://www.iras.gov.sg/ESVPortal/employers/employers_q1.2.1_faqs+on+tax+clearance.asp