SINGAPORE - Six Singaporeans have been arrested for drug offences after a Singapore-registered car was stopped by officers from the Immigration & Checkpoints Authority (ICA) for checks at the Woodlands Checkpoint on Thursday (April 14) morning.

In the course of inspection, officers found four blocks of cannabis weighing about 4kg and one bundle of Ice weighing about 310g, ICA said in a joint statement with the Central Narcotics Bureau (CNB) on Friday.

The driver, a 25-year-old male Singaporean, and the seized exhibits were referred to CNB for further investigations. He was later arrested.

From follow-up investigations, CNB officers also arrested a total of three suspected traffickers - two male Singaporeans aged 25 and 26 and a 26-year-old female Singaporean - as well as two suspected abusers - two male Singaporeans aged 24 and 32.

A substantial variety of drugs were seized from the follow-up operation, including about 2.1kg of cannabis, 380g of Ice, 152 Ecstasy tablets, 102 Erimin-5 tablets and 18g of heroin.

The estimated worth of the entire haul of drugs seized is more than $418,000, ICA and CNB said. Investigations into the drug activities of all arrested suspects are ongoing.

Under the Misuse of Drugs Act, those convicted of trafficking in more than 500g of cannabis and those convicted of trafficking in more than 250g of methamphetamine may face the death penalty.

In their statement, ICA and CNB said Singapore's borders are the country's first line of defence in safeguarding homeland security, and security checks are critical to the nation's security.

"The Home Team agencies will continue to conduct checks on passengers and vehicles at the checkpoints to prevent attempts to smuggle in undesirable persons, drugs, weapons, explosives and other contrabands."