Workers at Iraq's South Oil Company are holding a one-day strike to demand a bigger share of the country's oil revenues for the region.
Oil workers say they deserve a bigger cut of export revenues
The southern city of Basra and the region around it produce most of Iraq's crude exports.
Provincial governor Mohammad al-Waili, who called the strike, has called for the province to be allowed to keep more of the oil revenues.
But the oil firm said there would be minimal disruption to supply.
"This will be a peaceful protest, and will not lead to a halt in exports," one oil official told the Reuters news agency.
Oil production, on the other hand, stopped at most installations in the province as some 15,000 workers downed tools, Reuters said.
Earlier, agencies said exports could be halted by the strike.
Iraq currently exports about 1.4 million barrels of crude oil a day. Of that, more than 80% comes through the south of the country, with the remainder flowing out through a pipeline into Turkey to the north.
The export income amounts to some $17bn a year.
Too little of that makes its way back to the south, the provincial governor's party says, leaving the province short of money to improve living standards.