Iraq’s parliament voted on Saturday to integrate the controversial Popular Mobilisation Units (PMUs) into the country’s armed forces.

The law says the more than 100,000 PMU fighters will be subject to military law. They will answer directly to the Iraqi prime minister and be paid according to Iraqi Security Forces rates.

All the Shia blocs in the Iraqi parliament approved the measure, but many Sunni politicians, who have long accused the PMUs of engaging in sectarian reprisals against Sunni citizens, boycotted the session.

“I don’t understand why we need to have an alternative force to the army and the police,” said Sunni member of parliament (MP) Raad al-Dahlaki.

“As it stands now, it would constitute something that looks like Iran’s Revolutionary Guard,” he warned.

The move to normalise the PMUs has been in the works for some time, but the power and influence of the militias is such that the government has had great difficulty in getting the legislation approved.

Iraq analyst Joel Wing previously described the new move to integrate the PMUs on Twitter as "unenforcable".

"The purpose of the order is to try to gain control of the PMU," said Wing, speaking to Middle East Eye,

"It could also lead to conflict and violence as well, because many of the most powerful PMU groups have their own agendas and will not listen to [Prime Minister Haider al-] Abadi."

Terrible idea. PMUs will damage professionalism of the Iraqi Army & undermine trust of Sunni Arabs & Kurds in forces meant 2 protect them https://t.co/0BO7qRicD4 — Eric Davis (@NewMidEast) November 23, 2016

While there are as many as 30,000 Sunni PMU fighters and one Christian PMU grouping, the militias are overwhelmingly Shia-dominated, and a number have links to Iran.

Osama al-Nujaifi, one of Iraq's three vice presidents and a senior Sunni politician, told a news conference after the vote that he was alarmed by what he described as a “dictatorship” of the majority.

"The majority does not have the right to determine the fate of everyone else," he said.

"There should be genuine political inclusion. This law must be revised."

Despite the controversy, the PMUs are immensely popular in much of Iraq, where they have been largely the most effective fighters against the Islamic State group.

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

But many in the political establishment now fear the growing popularity of the PMUs, which are seen as heroic in comparison to politicians, whom many consider to be 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.