Protesters have blocked the entrance to Iraq's Khor al-Zubair commodities port near Basra, preventing trucks entering as the biggest wave of anti-government demonstrations in decades continue.
Khor al-Zubair is Iraq's second main Gulf port. It is used to export cargoes of gas condensates and receives refined oil product shipments, construction and electrical commodities and food.
"Unloading operations of commodities and goods which need to be transported by trucks have been completely halted," said one official.
At least 315 people have been killed since the start of mass unrest in Baghdad and southern Iraq in early October, the largest demonstrations since the fall of Saddam Hussein in 2003.
Protesters are demanding the overthrow of a political class seen as corrupt and beholden to foreign interests. Unsatisfied by government reform promises they see as meagre, many have turned to civil disobedience.
Oil officials said operations at a separate terminal, located near Khor al-Zubair and used to export cargoes of gas condensates, were not affected by Tuesday's blockade.
Imports of refined oil products were also unaffected as they are received via pipelines.
The closure of Khor al-Zubair comes a day after protesters again blocked the entrance to Iraq's Umm Qasr commodities port near Basra, preventing employees and tankers entering.
Umm Qasr port officials said operations had been completely halted there on Tuesday, after it was working at half capacity the previous day.
Australian Associated Press