Iraqi Prime Minister Haider al-Abadi on Sunday proposed scrapping top government posts and curbing privileges in an ambitious reform drive sparked by swelling popular anger over corruption and poor governance.

The proposed reforms followed weeks of demonstrations and a call for tougher reform measures from top Shiite cleric Grand Ayatollah Ali al-Sistani, who is revered by millions of Iraqis.

Amid a major heatwave that has seen temperatures top 50 degrees Celsius (120 degrees Fahrenheit), protesters have railed against the poor quality of services, especially power outages that leave just a few hours of government-supplied electricity per day.

But even with popular pressure and Sistani's backing, the entrenched nature of corruption in Iraq and the fact that parties across the political spectrum benefit from it will make any efforts to change the system extremely difficult.

One of the most drastic proposals outlined by Abadi was the call to scrap the posts of vice president and deputy prime minister "immediately".

The cabinet approved the reform plan on Sunday, Abadi's office said, but changes such as abolishing the posts would apparently require constitutional amendments, which would necessitate parliamentary action.

The three vice presidential posts, which have more privileges than responsibilities, are held by former top officials -- Abadi's predecessor and main rival Nuri al-Maliki, ex-parliament speaker Osama al-Nujaifi and former premier Iyad Allawi.

- Maliki support -

Maliki and Nujaifi said Sunday that they supported the reform drive, indicating that the proposed changes may be part of a deal they endorsed.

Allawi, meanwhile, issued a lengthy and at times bitter statement casting himself as a long-time supporter of changes such as those proposed.

Abadi's reform plan calls for a major overhaul of the way senior officials are selected, saying that "political and sectarian quotas" should end, and the candidates chosen by a committee appointed by the premier.

No quotas are enshrined in the constitution, but the patronage system grants many government jobs according to sect and party affiliation rather than merit.

Another proposed change is a "comprehensive and immediate reduction" in the number of guards for officials.

This has long been a problem, with some officials having massive personal protection units, and others hiring fewer than the allotted number and pocketing the rest of the allowance.

The plan also calls for ending "special provisions" for senior officials, both current and retired, and reducing the "high level" of pensions that have drawn repeated criticism.

The reforms also include a series of measures to strengthen anti-corruption oversight and otherwise combat graft, while others are aimed at streamlining the government, reducing waste and improving much-maligned services.

The announcement of the reform programme came two days after Sistani called for Abadi to take "drastic measures" against corruption, saying that the "minor steps" he had announced were not enough.

- System is 'rotten' -

One of those whose position is on the chopping block is Bahaa al-Araji, an unpopular deputy premier in charge of energy affairs who was apparently chosen as the first high-profile example of the anti-corruption drive.

Chief prosecutor Abdel Sattar Bayraqdar's office announced Sunday that the anti-corruption court has been ordered to investigate allegations against him.

Araji, a member of prominent Shiite cleric Moqtada al-Sadr's party, announced his resignation but said he was ready to fight graft accusations in court.

Despite having popular support, Abadi's efforts face major challenges.

"The entire system of government is rotten. The constitution is decrepit, the legal framework is woefully inadequate and the political class is utterly corrupt and incompetent," said Zaid al-Ali, author of "The Struggle For Iraq's Future".

"All political parties that are part of government profit directly from the current system, which is why it has remained unchanged since 2005," said Ali, a constitutionalist.

Thousands of people have turned out in Baghdad and the Shiite south to vent their anger at the authorities.

Various parties and politicians have sought to align themselves with the protesters -- at least in their rhetoric -- to take advantage of the movement and mitigate the risk to themselves.

And while people have protested over services and corruption before, those demonstrations failed to bring about significant change.

Late Sunday, hundreds of demonstrators gathered in Baghdad's Tahrir Square, criticising MPs and other politicians and saying they supported Abadi's reforms, but that further steps were needed.

"The decisions are the first step of liberating Iraq from corruption," said Samih Khalil, a demonstrator.

But he and others also warned that if the government does not follow through, the protests will continue.