Acting on specific information, Custom sleuths intercepted a Rajasthan-registered truck at Ramnagar area of the district, they said.
"We have seized nearly 500 kg of cannabis concealed in a false cavity specially built for the purpose on the rooftop," Deputy Commissioner of Custom (Preventive), North East Region, L Ralte told PTI.
He said the narcotic weighing about 476 kg was seized and the handler was arrested.
The truck bearing registration number was stopped near the Inter State Bus Terminus, Ramnagar, and the seizure was made.