Iraq's prime minister has said that his country faces at least two more years of widespread power shortages like the ones that sparked protests across southern Iraq.

Nouri al-Maliki said at a news conference on Tuesday that new power plants will eventually add 9,000 megawatts to Iraq's meagre power supplies.

But he said construction will take several years.

"The power stations being built by Siemens and GE will take two years to complete, at least," al-Maliki said, referring to the companies building the new power plants.

"The electricity problem cannot be over in one or two days."

Siemens and GE signed multi-billion-dollar agreements in 2008 to build the plants.

But the Iraqi government has struggled to pay the first instalment of those contracts.

It recently finished selling $2bn worth of bonds which will be used to pay for the power plants.

Al-Maliki also promised to increase the power supply to southern Iraq, where at least one person was killed last week during three days of violent protests.

Protesters criticised

Basra witnessed the largest demonstration: hundreds of people threw stones and empty bottles at the provincial government building.

He criticised the protesters as "rioters".

"There is a difference between demonstration and unrest. In Basra, it was unrest," al-Maliki said.

Thousands of people turned out for a peaceful protest in Karbala on Tuesday, and a smaller group demonstrated in the western city of Ramadi.

Al-Maliki also said he would consider a resignation offer from Kareem Waheed, Iraq's electricity minister. Waheed offered to step down on Monday.

But al-Maliki denied reports that he had demanded Waheed's resignation, and said the minister remains the best-qualified person to improve Iraq's electricity production.

"I don't know anyone in Iraq who is more capable than he is at the technical level," al-Maliki said.