Two long-time parliamentary allies are distancing themselves from Iraqi Prime Minister Nuri al-Maliki ahead of April elections, accusing him of a deeply flawed security policy and nepotism.

The allegations by key Maliki supporters Izzat Shabander and Sami al-Askari echo those of the Shiite premier's opponents, who charge that heavy-handed tactics by the police and army against Iraq's Sunni Arab minority have fuelled a sharp escalation of violence this year.

First elected premier in 2006, Maliki retained the post in 2010, buoyed by a sharp decline in unrest that followed a military offensive he ordered against the militia of Shiite cleric Moqtada al-Sadr in 2008.

But his security credentials have been badly dented by a resurgence of violence that has seen more than 6,200 people killed so far this year.

Critics say Maliki should have realised that heavy-handed tactics such as mass arrests and the closing off of entire neighbourhoods were alienating Sunni Arabs.

"A year is enough time for a person to change," Shabander told foreign correspondents in Baghdad.

"A nationalist is one in thought, in ideology and culture -- and in addition, by practice. He is a nationalist by ideology and aspiration, not a sectarian. ... (But) his poor security tactics have put him in a sectarian position."

Shabander, who was elected to parliament on Maliki's State of Law list in 2010, last week announced he was breaking away to run as an independent in the April 30 poll.

"Maliki has no other solution, other than confrontation," Shabander said, speaking at his home in the upscale Harithiyah neighbourhood.

"He does not have any other way to tackle problems.

"For example, the nature of the random arrests creates a sectarian gap.

"Two hundred people are arrested in a village, even though only 10 are wanted, so 190 people think that the only reason they were arrested was because they were Sunni.

"That practice is sectarian."

Shabander said Maliki needed to change the tactics of the security forces quickly, and do more to win back Sunni-majority areas of northern and western Iraq where there have been persistent protests for nearly a year.

Analysts say that while most Sunnis do not actively support militants, a lack of faith in the government has made many reluctant to cooperate with the security forces in counter-insurgency operations.

The result has been a dramatic rise in the death toll.

November's 692 people killed represented a four-fold increase over the same month a year ago, according to an AFP tally.

'They have nothing on me'

Maliki has also faced accusations of nepotism, particularly over the employment of his son Ahmed as deputy head of his office.

The issue was brought to the fore after Maliki defended some of his son's actions in a recent television interview that drew widespread derision.

Maliki confirmed to Al-Sumaria television that his son, a civilian, had commandeered a group of policemen to execute an arrest warrant against an allegedly corrupt contractor residing in Baghdad's heavily fortified Green Zone complex, home to the US embassy and parliament.

"The problem of Ahmed is that they want to defame Maliki, and they have nothing on me," the premier said of his critics.

Asked why his son had carried out the arrest warrant, the premier replied: "Because he is tough in his implementation (of rules), and because he is the son of Maliki."

Askari, who is also breaking away from the prime minister's list to form his own bloc, said Maliki was not the only Iraqi politician to hand jobs to members of his family but that the practice was still wrong.

"This was wrong," he said. "When they talk about Ahmed, it's not Ahmed, a small officer in the office.

"No, he is Maliki's son. So his word, his decision, it will be taken as (that of) Maliki."

Speaking to foreign correspondents in Baghdad, Askari said he had broached the issue with the prime minister several times but Maliki had disagreed with him.

Askari said he still backed the premier but was forming his own party to reach out to disaffected voters whom Maliki, with his roots in Shiite religious politics could not, such as the secular, women and the young.