Cape Town — A navigation warning has been issued to all vessels along the South African coast after 21 containers were washed off a container ship near Cape Town.

Three of the containers are tanks containing the hazardous chemical cresylic acid and two of these have already washed ashore - one at Camps Bay and the other at Sea Point.

The Safmarine Meru lost the containers in severe sea conditions while on her way from Port Elizabeth to Cape Town on Tuesday, said Safmarine spokesperson Debbie Owen.

The ship was battling gales gusting at over 100km/h and 12-metre swells.

The acid, classified as a Class 6.1 non-marine pollutant, was not considered a threat to the marine environment, but was dangerous at full concentration on land. Hazardous materials experts this morning began removing the two containers from the beaches, wearing protective clothing.

Safmarine has since appointed Svitzer Salvage to locate and recover the lost containers.