Join Date: Oct 2011
Location: Anywhere I need to be.
Programs: OW Emerald, *A Gold, NEXUS, GE, ABTC/APEC, South Korea SES, eIACS, PP, Hyatt Diamond
Posts: 16,046
From what I remember there is no duty free allowance going into Singapore from Malaysia (and also no allowance as you would have had to reenter Singapore within 48hr of leaving.)
That means that you would have to pay GST on the goods upon entry to Singapore and claim a refund on the way out.