Two people were killed and 10 others injured after a fire broke out on Friday at a gas liquefaction unit in Kuwait's largest refinery, the plant's operator said.

The blaze "erupted during maintenance work" on the unit at Mina al-Ahmadi refinery, 40 kilometres (25 miles) south of Kuwait City, state-owned Kuwait National Petroleum Company (KNPC) announced on Twitter.

Having initially said that 10 people were injured, it later updated its casualty toll, saying two workers "of Asian nationality" had been found dead at the site.

Seven of those injured were hospitalised, five of them in "critical condition", KNPC added.

Firefighters were mobilised and had extinguished the blaze.

Oil Minister Mohammed al-Fares later visited the site of the fire.

KNPC said Kuwait's refining operations and exports were unaffected, as the unit had already been out of service.

Mina al-Ahmadi, where another fire last October caused a number of light injuries, is the largest of Kuwait's three refineries and handles some 466,000 barrels of oil per day.

A fourth is under construction with a daily capacity of 615,000 barrels.

A key member within the Organization of Petroleum Exporting Countries (OPEC), Kuwait is currently producing about 2.4 million barrels a day.