Plumes of smoke rose above the Mina al-Ahmadi facility, located on the Gulf coast just opposite Iran, about 40 kilometres (25 miles) south of the capital Kuwait City, according to an AFP photojournalist.

The Kuwait National Petrol Company, after initially stating that there were no casualties, later tweeted that there were a number of injuries and cases of smoke inhalation among workers.

It said that those injured had received first aid at the site, or been transported to a hospital and were in a "stable condition".

Approximately two hours after the company reported firefighters were at the scene, it tweeted that the blaze was under "full control".

The Mina al-Ahmadi refinery, on a 10.5 square kilometre site, began operating in 1949.

It is the largest of three refineries of the state petrol company, producing about 466,000 barrels of petrol per day.

A fourth refinery with a production capacity of 615,000 barrels per day is under construction and set to begin operation by the end of the year.

The oil-rich Gulf emirate produces about 2.4 million barrels of petrol per day, most of which is exported.