Four containers that fell overboard from a Zim containership off Canada on Friday have come ashore in Vancouver Island's Cape Scott.

The 4,253-teu Zim Kingston (built 2008) lost at least 109 boxes when it ran into stormy weather about 5 nautical miles (9.26 km) from the Port of Vancouver, according to latest estimates from the Canadian Coast Guard (CCG).

The CCG originally reported that 40 boxes had gone overboard, two of which contain the hazardous mining chemical potassium amyl xanthate and have yet to be found.

"This afternoon our helicopter spotted four containers from the M/V Zim Kingston onshore near Cape Scott, where the Environmental Unit’s drift modelling predicted they would land," the CCG wrote on its Facebook page on Wednesday.

"It appears that at least one of the containers, containing refrigerators, has broken open."

The CCG said shipowner Danaos Corp has hired a contractor to recover the containers that went overboard from the vessel, upon which several boxes caught fire during the incident.

"Right now the contractor and Unified Command have positively identified the four containers found at Cape Scott by cross-referencing the ship’s manifest, and have confirmed they are not considered dangerous goods," the CCG said.

The location is remote and rugged, and planning for recovery operations is underway."

Unified Command is still looking for more containers from the Zim Kingston via aerial patrol.

The ship, which is carrying almost 2,000 containers, is anchored 4.7 nautical miles offshore while salvage experts wait to remove or secure damaged boxes once the fire is fully extinguished.

Transport and Infrastructure Canada inspectors will then board the ship to determine and oversee any necessary repairs before directing it to a nearby port for unloading and further inspections.