A top official in the office of the Divisional Deputy Excise Commissioner said the two, who were coming from Palakkad, were allegedly attempting to smuggle the drug.
The excise department was investigating if they were going to the Kochi International Airport to smuggle the drug to some international destination, he said.
The department was also investigating from where they secured the drug.
This is the biggest ever drug seizure in the state since January when the Narcotics Control Bureau sleuths seized cocaine worth Rs 25 crore.
A Filipino woman, who had landed at the international airport here from Muscat, was arrested at that time with 4.5 kg of cocaine in her checked-in baggage.
She was travelling from Sao Paulo to Addis Ababa and from there to Kochi via Muscat.