Massive rallies broke out in Iraq's capital and south this month against corruption and unemployment, spiralling into angry calls for a total government overhaul.

In the latest week-long wave of demonstrations, at least 100 people have died and 5,500 more wounded, the Iraqi Human Rights Commission said.

The commission told AFP most of the casualties were civilians who either suffocated by tear gas, sustained trauma wounds from tear gas canisters or were shot dead.

The number brings the toll since protests first erupted on October 1 to 257 dead and more than 10,000 wounded.

But demonstrators turned out regardless on Wednesday, waiting to see whether the first fruit of their struggle -- the ouster of Prime Minister Adel Abdel Mahdi -- was finally within reach.

They flooded Tahrir Square in Baghdad, and a cacophony of honking horns, fireworks and blasts from tear gas canisters used by security forces could be heard from nearby districts.

As thousands streamed into the chaotic square, quiet talks were underway among the country's leaders over the premier's fate.

Abdel Mahdi, 77, came to power last year through a tenuous partnership between populist cleric Moqtada Sadr and paramilitary chief Hadi al-Ameri.

But the premier appears to have lost top-tier support, with Sadr calling for his resignation and early elections.

President Barham Saleh held talks with Speaker of Parliament Mohammed al-Halbussi and Ameri late Tuesday over the premier's ouster, an Iraqi government source told AFP.

And parliament has demanded that the premier appear "immediately" for questioning amid speculation he will face a no-confidence vote.

- No alternative? -

The kingmakers' alliance between Sadr and Ameri has been ruptured by protests, with Sadr's Saeroon bloc, the biggest in parliament, endorsing the demonstrators.

The Hashed al-Shaabi paramilitary force, whose political arm Fatah is parliament's second-biggest bloc and is chaired by Ameri, has so far backed the government.

Several Hashed offices were torched in southern Iraq last week, further straining ties.

But Sadr extended an invitation to Ameri late Tuesday to coordinate on a no-confidence vote in Abdel Mahdi and used Twitter to urge the premier to "Get out!"

Hours later, Ameri announced he and Sadr would "work together to achieve the people's demands," hinting he may agree to a vote on the premier's future.

Sadr took to Twitter again on Wednesday to pile on pressure, warning that keeping Abdel Mahdi would "turn Iraq into Syria or Yemen" -- countries both engulfed in bloody wars.

Meanwhile, Iran's supreme leader Ayatollah Ali Khamenei told Iraqis they should find legal ways to resolve crises instead of hitting the streets.

"The people of Iraq and Lebanon have some demands that are rightful, but they should know these demands can only be realised within the legal frameworks," said Khamenei.

The United Nations' top representative in Iraq, Jeanine Hennis-Plasschaert, called again for a national dialogue to "unite against the perils of division and inaction."

- 'Back to square one' -

Athir Malik, 39, came from Diwaniyah, 200 kilometres (130 miles) further south, to join the rallies on Wednesday.

"Isn't it the people who have the power? Isn't it the people who put them all there?" he asked.

Demonstrators have shrugged off a litany of government reform plans and called for a new constitution, reworked electoral law and mass resignations from a government they see as corrupt.

"They should all quit and we should have a national salvation government," said Alaa Khdeir, 63.

While the premier's departure would be seen as a "victory" for demonstrators, it would "give protests a break but not break them," said Maria Fantappie, an Iraq analyst at the International Crisis Group.

"Even an election with the same election law would bring (the) same figures into parliament and the same process as last year in selecting the prime minister, which puts you once again at square one," Fantappie said.

Since the US-led invasion that toppled dictator Saddam Hussein in 2003, Iraq's political system has been gripped by clientelism, corruption and sectarianism.

The country is ranked by Transparency International as the 12th most corrupt in the world.

That means getting a job in government -- by far the country's biggest employer -- is often secured with bribes or connections.

Anger at the state of affairs had been swelling among the youth, who make up 60 percent of Iraq's nearly 40 million people.

Youth unemployment stands at 25 percent, while one in five live below the poverty line, despite the vast oil wealth of OPEC's second-largest crude producer.