One of Kuwait's three oil refineries was still offline on Thursday after a power cut shut all of them down on Wednesday, a spokesman for Kuwait National Petroleum Company (KNPC) said.

The 200,000 barrel per day (bpd) Shuaiba refinery had not yet restarted on Thursday morning, while the 460,000 bpd Mina Ahmadi and 270,000 Mina Abdullah refineries are not expected to be back to full production until Friday.

"We managed to start the Ahmadi and Mina Abdullah refineries and started to pump oil through them and we are still trying to run the Shuaiba refinery," he said.

Power cuts are common in the Gulf Opec oil producer because of an antiquated and unstable electricity supply system.

The three refineries were built next to each other on the Gulf coast south of the capital. - Reuters