Iraq's parliament gave embattled Prime Minister Haider al-Abadi until Thursday to present a cabinet of technocrats as Shiite cleric Moqtada Sadr expanded his protest movement for reform.

Sadr himself spent the night camping in the Green Zone while thousands of his supporters continued a 10-day-old sit-in outside the gates of the fortified area in central Baghdad.

"Parliament is the legitimate representative of the people and it declared that Thursday is the final deadline for the government to present a new ministerial line-up," the speaker's office said in a statement on Monday.

Sources in parliament told AFP that 170 lawmakers out of 245 present voted in favour of the deadline.

"If Abadi fails to present his new cabinet, he must be present in parliament on Saturday to explain why," said Haidar al-Mutlaq, an MP from the State of Law bloc.

Abadi has promised to reshuffle the government by replacing party-affiliated ministers with technocrats, a move meant to help tackle corruption and Iraq's massive budget crunch.

The premier has faced resistance from ministers within his own Shiite bloc who are reluctant to give up their positions and attendant privileges.

Abadi already faces pressure from the street in the shape of the sit-in by Sadr's supporters at the gates of the Green Zone, which is home to his office, parliament and several large Western embassies.

Sadr had warned that his supporters would storm the Green Zone if Abadi failed to present a line-up of technocrats.

But buying Abadi a little more time, Sadr entered the Green Zone alone on Sunday, asking his supporters to remain outside the perimeter.

The Sadrist movement also staged protests in the holy Shiite city of Najaf, where Sadr is usually based, as well as in Basra, Hilla and Kut.

"This demonstration is a message to the leaders from the Green Zone, telling them that Sadr represents all Iraqis," said Hadi al-Denienawi, the head of Sadr's office in Najaf.

Falah Mohammed Hassan, 47, was among thousands who demonstrated in the southern port city of Basra.

"The aim of this protest is to call for change and reforms. The only thing we will accept is a cabinet of technocrats, we will topple all the corrupt and make them accountable," he said.

Many leading Iraqi politicians live inside the Green Zone, a sprawling area the US army sealed off after invading Iraq in 2003.

The restricted zone is now seen as an egregious symbol of the privileges enjoyed by the ruling elite and the corruption that has stunted the development of the oil-rich country.

The scion of an influential clerical family from the holy city of Najaf, Sadr first made a name for himself at the age of 30 as a vociferous anti-American cleric who raised a rebellion.

His influence ebbed after the 2011 US pullout but he retained strong support among the lower classes and is now casting himself as the champion of the fight against graft.