Malaysian police have seized more than one million dollars worth of heroin in the country's biggest seizure in years, reports said Tuesday.

Officers recovered 77 kilograms of the drug worth RM3.85 million during raids that netted 11 suspects last Friday, The Star said, citing police.

"We are investigating the source of their supply and are tracking down other members who are still at large," Mohammed Bakri Mohammed Zinin, director of the federal anti-narcotics police, was quoted as saying.

He added it was the biggest heroin seizure since 2001.

"Neighbouring countries were used as transits before the heroin was smuggled into our country," national police chief Musa Hassan said, according to the state Bernama news agency.

The syndicate put police and other official stickers on their cars to avoid suspicion, The Star quoted Musa as saying.

In May, police said they had seized almost 13 kilograms of heroin and arrested eight people after another operation.