Disguised as a regular shipping containers, they can be sneaked on board a vessel to blend in seamlessly with the hundreds of others on board.
The sheer number of container ships in the world makes them harder to pinpoint than warships in the event of war.
Like the fabled Trojan Horse, the missiles would be quietly smuggled into or near an enemy port on a civilian vessel before being unleashed in a surprise attack.
Rick Fisher, senior fellow in Asian military affairs at the International Assessment and Strategy Center, told The Sun Online while Chinese have not officially confirmed they have the missiles – it is likely they have them.
And the it was warned in a study by Stockton Center for International Law that the weapons could violate naval laws.
Meanwhile, retired Navy Capt. Jim Fanell, a former Pacific Fleet intelligence chief, previously said a containerized anti-ship missile would add a significant threat to the US Navy.