When the heat inside prison became unbearable for the corrupt former governor of Iraq's Salaheddin province he offered to stump up the money himself to air-condition the whole jail.

The authorities readily accepted. After all, this was one way of recuperating some of the cash the former official had skimmed from state coffers.

After three years battling jihadists of the Islamic State group, the authorities have now set their sights on fishing for "sharks".

This is the popular phrase for the fight against senior officials who have acted with total impunity to line their own pockets.

According to anti-graft organisation Transparency International, Iraq is one of the most corrupt states in the world.

It currently slots in at 166th place out of 176 nations, with a score of just 17 out of a possible 100 on the honesty scale.

Prime Minister Haider al-Abadi has said he is committed to a "ruthless" fight against corruption, which he compares to the struggle against "terrorism".

But this is an enormous challenge in a country where graft is one of the levers used to maintain the balance of power and distribution of ministerial posts since the US-led invasion in 2003.

"Most parties see state institutions as a source of funding for their political activities," political scientist Ihssan al-Shamari of the Tafkir research centre told AFP.

- Money in, money out -

For more than 13 years, governments have been formed following shady "deals between politicians to cover the corrupt".

The former governor of Salaheddin province north of Baghdad has not been the only official to fall foul of the anti-corruption committee, which reports to Abadi.

In a sign of official determination to tackle the wide-ranging scourge, the state spotlight has also swung onto the boss of national carrier Iraqi Airways, who has been arrested despite his political connections.

For years Iraqis have denounced the bad management and financial negligence that have stifled the country and let its infrastructure fall apart despite the injection of billions of dollars.

Since the invasion, oil may have provided more than $800 billion in revenue, but corruption has cost the country $312 billion, according to the Injah Centre for Economic Development.

As ever-present security problems have receded in recent months with the success of the anti-IS campaign, a number of officials have found themselves in the anti-graft crosshairs.

Take the former chief of General Company for Agricultural Supplies, a public body.

He was incarcerated for embezzling $26 million, but was later arrested on the border with Iran after escaping from prison with the help of a former deputy.

- 'A chronic phenomenon' -

However, half a dozen ministers have managed to avoid the dragnet, and got away with billions of dollars.

In many cases of corruption, the amounts and details of the transactions involved have not been pinpointed or even investigated.

Jassem al-Halfi, a citizen pioneer of the anti-corruption movement, believes the moves made so far are a good start.

"But we are still far short of the target as corruption has become a chronic phenomenon infecting every state institution," he told AFP.

Halfi insisted that the anti-graft campaign must also include "the big fish, businessmen and promoters of phantom projects in cahoots with corrupt state officials".

He cites $40 billion invested in the country's power grid being skimmed off, meaning Iraqis have to rely on expensive generators to provide them with more than just a few hours of electricity a day.

Social networks have long sought to highlight the distribution of the fruits of corruption in Iraq.

One recent post on Facebook showed a palm tree, the country's national symbol, with a tower of people underneath.

"This is how corruption climbs in our country: there are those who have stolen and fled, those who are still stealing and those awaiting their turn once the sharks are full," the commentary reads. 

Political pundit Tareq al-Maamuri told AFP: "Haider al-Abadi has begun reeling in big fish because corruption has reached an unimaginable level."

But he also said that because state finances have been brought to their knees by the fall in world oil prices, the country "can no longer afford to support" corruption.