Iraqi militias accused of human rights abuses in the campaign against the Islamic State group are to be placed on par with elite army units and subject to military law, according to a statement from the prime minister's office.

The Popular Mobilisation Units (PMUs), which have played an important role in seizing back territory from IS, are to be depoliticised and subject to military law, the statement from Haidar al-Abadi said.

The statement stipulates that “politics” would be banned within PMUs, often known as Hashd or Shia militias despite comprising a number of sects.

"Members of the Hashd who are part of this body are to have no links to any political, party political or social framework,” read the statement, released on the English-language PMUs Twitter feed on Tuesday.

“It is not permitted to carry out political work within its ranks.”

A spokesperson for the PMUs told Middle East Eye that the change would put the PMUs on par with the elite Counter-Terrorism Forces who have been deployed against Islamic State in Fallujah.

“We are now under command of the prime minister's office currently held by Haider Al-Abadi,” explained the spokesperson.

Officially, command of the PMUs had up until this point fallen under the remit of Abu Mahdi Al-Muhandis, a former leader of Kataib Hezbollah, though different militias ultimately followed the orders of their pre-existing leaders.

Iraq analyst Joel Wing described Abadi new initiative on Twitter as "unenforcable". Others commentators noted that the document was dated from February and had apparently taken months to circulate.

"The purpose of the order is to try to gain control of the PMU," said Wing, speaking to Middle East Eye, who added that as a result of the order, militias would be placed under military law and be paid according to the Iraqi Security Forces rates.

"It could also lead to conflict and violence as well because as I said many of the most powerful PMU groups have their own agendas and will not listen to Abadi."

The announcement comes as the Iraqi military and its allies continue to build for the assault against the northern city of Mosul, the last Islamic State stronghold in Iraq.

The role of the PMUs in liberating the city has been controversial - a number of them have been accused of committing human rights abuses and carrying out sectarian retributions against Sunnis.

During the recent assault to liberate the city of Fallujah, the PMUs were prevented from entering the centre of the city for fear of sectarian reprisals. In the end, reports of torture and extrajudicial killings still flowed from the areas where the militias were operating.

While there are Sunni PMUs and one Christian PMU, the militias are overwhelmingly Shia-dominated and a number have links to Iran.

In November, Akram al-Kaabi, leader of the Harakat al-Nujaba militia, said that he would overthrow the Iraqi government were he ordered to do so by Iran’s Supreme Leader Ali Khamenei.

Other PMU fighters, however, have argued that they are more effective fighters against IS than the regular army as well as less indiscriminately destructive of the cities they liberate.

“Hashd al-Shabi are very clean fighters, very human,” said Abu Ezaaz, government liaison for the Ali Akbar Brigades, using an alternative name for the PMUs, speaking to Middle East Eye in May.

“For example, if some sniper is fighting you, the Hashd al-Shabi will try to use snipers against them, but if the military intervene, the city will be destroyed. If bullets come from a place, they will bomb and air strike that place.”

The PMUs were originally formed in 2014 after a call from leading Shia cleric Ali al-Sistani for Iraqis to fight against IS, following their June takeover of Mosul.

Many in the political establishment fear the growing popularity of the PMUs, who are seen as heroic in comparison politicians who are seen as corrupt and weak.

Mustafa Habib, writing for Iraqi analysis site Niqash, cited numerous militia leaders who had expressed an interest in taking part in the 2017 parliamentary elections.

"The existing Shiite Muslim-dominated political parties can clearly see the danger presented by the wildly popular militias," he wrote.

"Behind closed doors there are already negotiations underway between the political parties and the militias to form alliances, as it is clear that the militias will win many votes in 2017."

Joel Wing theorised that the new PMUs order by Abadi could be used as a means of preventing certain groups from participating in elections.