Four men were injured when a 23 000 litre oil tank exploded in Amanzimtoti on Sunday, KwaZulu-Natal emergency services said.

The cause of the accident, at the SATI Chemicals plant in Beechgate road, was not yet known, Netcare 911 spokesperson Jeff Wicks said in a statement.

"The injured men were rushed to Netcare Kingsway hospital for further medical care. One man sustained burns to his face and legs and has been admitted for treatment. The others sustained inhalation burns and will likely be discharged later today."

He said the explosion rocked surrounding factories and residential areas. Plumes of thick black smoke could be seen rising into the Amanzimtoti skyline.

"Word from firefighters is that the smoke is not hazardous and there is no cause for alarm. The tank is still in flames and there are fears that other containers nearby could fall victim to the blaze if it is not brought under control.

"eThekwini metro fire and emergency have called in resources from Durban central to assist."