I don’t think there are many true-to-the-classic-definition “brutalist” buildings remaining in Singapore. What you would get are buildings that might have leaned strongly toward brutalist tendencies in the past, and the design could still display aspects of it. Mandatory building maintenance laws and regulations mean that they would have all already underwent some form of renovation or face-lift during their lifetime, and could now have a smoother appearance over their original form, losing that rough exterior appearance of classic brutalist architecture.
I can only think of describing these as “modern brutalism”. No one builds buildings like these any more. The current trend leans towards either “organic curves” or a kind of “modern rectangular” that does not convey a similar level of “brutality”.