Two Afghan soldiers were arrested.
Police in southern province of Zabul say the discovery and arrests were made on March 15 during a routine security check on the main road connecting Kabul and Kandahar.
The discovery underlines statements by officials that say some soldiers and members of the security forces are actively involved in the country's drug trade.
Afghanistan is the world's largest producer of opiate-derived drugs. Despite international efforts to stem the trade, poppy cultivation in the country is expected to increase by up to 40 percent this year.