SINGAPORE - Two Malaysian men aged 18 and 23 were arrested at Woodlands and Tuas Checkpoints on Thursday evening, after drugs were found in the cars they were driving into Singapore.

The seized drugs - about 5.9kg of cannabis and 465g of heroin - had an estimated street value of more than $227,000, said the Immigration and Checkpoints Authority (ICA) and the Central Narcotics Bureau (CNB) in a joint news release on Friday.

ICA officers conducting a routine check on a Malaysia-registered car at Woodlands checkpoint at 7.55pm on Thursday found two blocks in white wrapping, suspected to be cannabis, in the front engine air filter compartment of the car.

CNB officers were then alerted, and a further search of the car uncovered four more blocks, suspected to be cannabis, hidden behind the backrest of the driver and front passenger seats.

The six blocks of suspected cannabis weigh around 5.9 kg and have an estimated street value of more than S$195,000.

Later that evening, at 9.45pm, ICA officers at Tuas Checkpoint conducting a routine check of another Malaysia-registered car found a black bundle in the car's arm rest compartment.

The bundle, suspected to contain about 465g of heroin with an estimated street worth of over S$32,000, was seized and handed over to CNB.

Investigations are ongoing.

If convicted of drug trafficking, both men face the death penalty.

Under the Misuse of Drugs Act, drug traffickers face the death penalty if the amount of pure heroin, or diamorphine, they bring in exceeds 15g. This is equivalent to 1,250 straws, which is sufficient to feed the addiction of about 180 abusers for a week. Those convicted of trafficking in more than 500g of cannabis may also face death.