Peruvian police have seized a record 6.5 tonnes of cocaine in a quiet coastal town this week, arresting seven Peruvians and two Mexicans suspected of trying to smuggle the load to Europe as coal, President Ollanta Humala has said.

The cocaine, captured in a warehouse on Tuesday in Huanchaco, near the city of Trujillo in northern Peru, was packed into brick-sized packets and glued inside large chunks of coal, according to images provided by the government, the Reuters news agency said.

Authorities have increased their initial estimate of three tonnes of cocaine since uncovering the illicit cargo. Police, who made the bust following weeks of investigations, are still examining the load.

The total amount of cocaine confiscated might surpass 6.5 tonnes, Humala said.

"This is, without doubt, the most important blow to drug trafficking in the history of the republic," he added.

Peru is the world's top cocaine and coca producer, according to the US and UN. Coca is the plant cocaine is extracted from.

The export companies linked to the smuggling operation have been exporting coal to Spain and Belgium since at least 2011, police said.

The suspects arrested are likely to belong to an important global drug cartel, Daniel Urresti, the Peruvian interior minister, said, declining to identify which one.

Source: Agencies