A crude oil distillation unit (CDU) at Kuwait's Mina Al-Ahmadi refinery has been shut for maintenance which is expected last about a month, a spokesman for the Kuwait National Petroleum Company (KNPC) said on Monday.

"The unit has been shut exactly last Sunday," the spokesman for the operator of the OPEC member's three refineries said, adding that the other two CDUs were running normally.

The total capacity of the three CDUs in Mina Al-Ahmadi is 466,000 barrels per day (bpd), making it Kuwait's largest refinery.

A Gulf-based oil trader said the unit under maintenance has a capacity of around 130,000 bpd but said the outage would not impact KNPC's export commitments.

The KNPC spokesman also confirmed that maintenance has started at Kuwait's Shuaiba refinery, where a heavy oil unit is expected to be shut until November.

KNPC manages Kuwait's three refineries, Shuaiba, Mina Al-Ahmadi and Mina Abdullah, with a total capacity of around 930,000 bpd. – Reuters