The authorities seized drugs with a street value of about $183,000, including nearly 2kg of heroin, in a raid on Tuesday afternoon.
Four suspected drug offenders were also arrested following the raid at a Joo Chiat Place unit, the Central Narcotics Bureau (CNB) said in a statement yesterday.
They include two Singaporean men - a 48-year-old suspected drug trafficker and a 35-year-old suspected drug abuser - and a 33-year-old female foreign national arrested in the area.
CNB also arrested a 26-year-old Malaysian man at a traffic junction in Toh Guan Road.
Officers recovered $13,800 in cash from the man.
All four suspects are under investigation for drug activities.
In a search of the Joo Chiat unit, CNB officers found a total of 1.99kg of heroin, 424g of Ice, 15 Ecstasy tablets, 15 Erimin-5 tablets and a small amount of cannabis.
Various coloured substances, weighing more than 7.6kg and suspected to be Ice or ketamine, were also seized.
CNB said that the amount of heroin it found could feed the addiction of 950 abusers for a week.
The bureau added that 424g of Ice could do the same for 242 abusers over the same period.