Demonstrators cover themselves during a protest over corruption, lack of jobs, and poor services, in Baghdad. Reuters

Renewed anti-government protests across Iraq left more than 42 people dead on Friday through tear gas, live rounds and fires, a watchdog and security sources told the media.

UN seeks transparent probe into death of Iraqi protesters

The protests represent a second phase of a week-long movement in early October that ended with more than 150 people dead.

Rallies had been set to resume on Friday, with a range of actors from Iraq's highest Shiite authority to the United Nations urging restraint.

Activists urged Iraqis to return to the streets on Friday, which marks a year since Prime Minister Adel Abdel Mahdi came to power.

But the rallies began early, with hundreds already gathering in the capital's iconic Tahrir (Liberation) Square on Thursday evening.

Demonstrators carry a man who fainted from the effect of tear gas in Baghdad. Reuters

On Friday, many crossed the bridge to mass near Baghdad's Green Zone, which hosts government offices and foreign embassies, but security forces used a volley of tear gas to push them back.

"Two demonstrators died, with preliminary information indicating they were hit in the head or face by tear gas canisters," said Ali Bayati, a member of the Iraqi Human Rights Commission.

He said nearly 100 more were wounded, but there were no reports of live fire being used to disperse protesters in the capital.

In the southern city of Nasiriyah, however, medical and police sources told AFP that five protesters were shot dead and another 18 were wounded.

Thousands had gathered there in the afternoon, setting fire to the government's provincial headquarters.

An eighth protester died of burns sustained when demonstrators set fire to several political party offices in another southern town.

'All liars!'

"We're not hungry — we want dignity!" a protester shouted in Baghdad on Friday morning, while another lashed out at "the so-called representatives of the people who have monopolised all the resources."

One in five people lives in poverty in Iraq and youth unemployment sits around 25 per cent, according to the World Bank.

The rates are staggering for OPEC's second-biggest oil producer, which Transparency International ranks as the 12th most corrupt state in the world.

"I want my share of the oil!" another protester told the media.

Iraqi security forces arrest a protester during a demonstration in central Baghdad on Friday. AP

Iraq's highest Shiite authority Grand Ayatollah Ali Al Sistani had set Friday as the deadline for Abdel Mahdi to respond to demonstrators' demands.

In a much-awaited sermon, Sistani's representative urged protesters and security forces to show "restraint," warning of "chaos" if violence broke out again.

His sermon appeared to echo the package of reforms put forward by Abdel Mahdi, including an anti-corruption campaign, a job creation drive and improved social welfare.

But demonstrators did not appear impressed.

"Adel Abdel Mahdi is lying to us," protesters shouted in Baghdad, just hours after the premier's televised appearance in which he defended his reform agenda.

"They are all liars — they lie when they promise us jobs and when we protest, they fire tear gas at us!" shouted another.

Security forces unleashed tear gas canisters on Friday to disperse thousands of protesters around Baghdad's high-security Green Zone, which hosts government offices and embassies.

Sadrists on 'high alert'

But the real test was to be later in the afternoon, when many were expecting supporters of Moqtada Al Sadr — an influential cleric who controls the largest parliamentary bloc – to hit the streets.

His supporters have breached the Green Zone in previous years. This week, he called on them to protest and even instructed members of his own paramilitary force to be on "high alert."

They could be seen in parts of Baghdad on Friday in a clear show of force.

The movement is unprecedented in recent Iraqi history both because of its spontaneity and independence, and because of the brutal violence with which a torrent of protests on October 1-6 was met.

At least 157 people were killed, according to a government probe published on Tuesday, which acknowledged that "excessive force" was used.

A vast majority of them were protesters in Baghdad, with 70 per cent shot in the head or chest.