Production at Iraq's biggest oil field was partially halted on Saturday after two bombs damaged a pipeline transporting crude, the head of state-owned South Oil Co said.

The blasts occurred overnight in the Safwan bridge area southwest of the port city of Basra, and the Qarenat area west of there, near the Rumaila oil field and caused a fire, according to a police officer and an SOC official.

"Two explosions took place last night targeting the pipeline that transports crude oil from Rumaila South to Zubair," SOC chief Dhia Jaafar said at a news conference in Basra.

"Production has stopped on the southern side (of Rumaila). ... Technical staff are working non-stop now to solve the problem."

Output at Rumaila South is between 600,000 and 650,000 barrels per day (bpd), Jaafar said.

An SOC official, speaking on condition of anonymity, earlier said the blasts and ensuing fire, which has since been put out, did not affect exports.

The Rumaila field is the country's biggest, with proven reserves of 17.7 billion barrels of oil. Britain's BP and China's CNPC have had a contract to extract crude there since 2009.

Zubair is another field in Basra province and is exploited by an ENI-led consortium, which includes Occidental Petroleum Corp of the United States and Korea Gas Corp of South Korea.

Oil sales account for the lion's share of government income in Iraq, with the country exporting around 2.2 million bpd. That figure is set to rise by around 300,000 bpd early next year, according to the oil ministry.

Iraq currently produces around 2.9 million bpd, and says it will be capable of output of 12 million by 2017.