Brandishing banners and Iraqi flags, the non-partisan protesters streamed into west Baghdad's al-Nusoor square, demanding a complete political overhaul, according to footage carried by state media.

The mobilisation followed nearly 11 months of paralysis that has left the country without a new government, prime minister or president, with Shiite factions disagreeing on forming a coalition since elections last October.

Demonstrators shouted the Arab Spring slogan: "The people want the fall of the regime."

Others carried banners and sang slogans deploring interference by neighbouring Iran, according to videos and images circulating on social media networks.

"Iran will not rule anymore," they said.

The peaceful demonstrators were supporters of an anti-government protest movement that erupted in October 2019 but has since died down.

Their rallies in Baghdad are not rare but Friday's relatively large turnout came after Iraq's political crisis deepened.

Clashes between supporters of powerful Shiite cleric Moqtada Sadr and rival Iran-backed factions earlier this week turned the Green Zone -- home to government buildings and embassies -- into a battlefield.

Thirty Sadr supporters were killed in nearly 24 hours of clashes that erupted on Monday after his supporters stormed the government headquarters.

The violence moved to the country's south on Thursday where overnight clashes between Sadr-affiliated fighters and the rival Iran-backed Asaib Ahl al-Haq force left four militants dead.

Two members of Sadr's Saraya al-Salam force were among those killed.

The oil-rich country has been ravaged by decades of conflict and endemic corruption.

It is blighted by ailing infrastructure, power cuts and crumbling public services, and now faces water shortages as drought ravages swathes of the country.

Despite Iraq's oil wealth, many citizens are mired in poverty, and some 35 percent of young people are unemployed, according to the United Nations.