The withdrawal of the protesters gives Abadi some breathing room, but he has struggled to implement any meaningful political changes despite months of trying.
Sadr is demanding an end to a quota system, set up after the 2003 US-led invasion, under which political positions are divided up based on sect and ethnicity. Abadi has tried to put in place a technocratic government, but his attempts to reshuffle his Cabinet have been hampered by bickering in a split Parliament.
Patience ran out at the weekend as Sadr's followers entered the Parliament building. The cleric, who led an armed opposition against US troops during the Iraq War, has a strong following on the street and described the events as the beginning of a "revolution".
"History will record the birth of a new Iraq from the ashes of corruption and the corrupt," he said.
Security forces declared a state of emergency in the Iraqi capital on Sunday after the demonstrators climbed over blast walls and broke through security cordons to enter the fortified Green Zone.
MPs fled the Parliament building in panic, with some berated and struck by protesters as they left. Others were trapped in the basement for hours, too afraid to face the crowds.
History will record the birth of a new Iraq from the ashes of corruption and the corrupt
Obaidi said that if demands for a technocratic government are not fulfilled, then protesters will demand the sacking of the prime minister, the president and the speaker. If not, they will demand early elections, she said, adding that if all else fails, they would storm the headquarters of political leaders.
At the parade ground where demonstrators had gathered earlier in the day next to the Hands of Victory monument, an arch of crossed swords that commemorates the Iran-Iraq War, Sadr's supporters said they had expected a longer sit-in.
Some were arriving with supplies, pillows and blankets. "We have everything we need. We'll be there for as long as it takes," said Ahmed Majid, 25, carrying shopping bags and a blanket over his shoulders.
The chaos has cast doubt over Abadi's ability to steer Iraq out of its political crisis, which has been simmering since street protests against corruption and government waste began last northern summer.
Abadi's office released pictures of his tour of the ransacked Parliament building, surveying smashed windows and overturned furniture.