The ultimatum adds to the turmoil surrounding Iraq’s unity was sectarian violence continues to flare despite crackdowns and curfews by the US and Iraqi military.
“The letter endorsed by the Kurdish alliance, the Sunnis and Iyad Allawi’s group has been sent to the United Iraqi Alliance asking them to review their decision on Jaafari and select another candidate,” said senior Kurdish parliamentarian Mahmud Othman.
Earlier in the day Mr Othman said the groups felt Mr Jaafari was the wrong man to lead the next cabinet in the first permanent post-Saddam Hussein government.
“The Kurdish and the Sunni groups think that he (Jaafari) is not appropriate and they cannot form a cabinet with him as he is not neutral,” Mr Othman said.
Selected by one vote
The move is a latest setback in the tortuous process to form a government in the wake of December general elections.
Last month Mr Jaafari was re-selected, by just one vote, for the post of premier by the dominant Shiite alliance which won 128 of parliament’s 275 seats in the December elections.
Mr Jaafari’s selection must be formally endorsed by a new three-member presidential council. But the presidential council must itself be appointed by a two-thirds majority of parliament, which has not yet met.
The constitution stipulates that the prime minister must form his cabinet within 30 days of his appointment, failing which another can be appointed in his place.
Mr Jaafari, a doctor turned politician, now faces a growing opposition campaign.
His candidacy is opposed by two key political factions: the Kurds who are part of the outgoing government coalition and who control 53 seats in the new parliament, and the Sunni alliance known as the National Concord Front which controls 44 parliamentary seats.
Former premier Iyad Allawi, who controls 25 seats in the new parliament, has also raised objections to Mr Jaafari’s candidature.
“The prime minister should be somebody who is agreed upon by everyone. They (Kurds and Sunnis) have decided to talk to Shiites on this in the next couple of days,” he said.
Both groups view Mr Jaafari, who has run the government for much of the past year, as unsuccessful, said Mr Othman, who added “they think the experience with him has not been good and may lead to similar problems in future.”
Alaa Maki, a leader of the main Sunni-based party confirmed its objection to Mr Jaafari’s candidature.
“We have nothing against him (Jaafari) but his performance has been below expectations,” said Mr Maki, who is asenior leader of Islamic Party which is part of the National Concord Front alliance.
Jawad al-Maliki, a member of Mr Jaafari’s inner circle, told reporters he hoped “the authors of this letter will reconsider their position.”
Mr Maliki also warned that the stance could slow down the formation of the new government “because no list can for the government alone… any delay weighs heavy on the current security situation in the face of the terrorist challenge we are confronting.”
Mr Jaafari’s present term has been marked by a persistent insurgency and last week the government faced an outbreak of sectarian violence triggered by the bombing of a revered Shiite shrine which threatened to escalate into civil war.
Mr Jaafari has also came under strong criticism from President Jalal Talabani, a Kurd, for holding talks this week in neighbouring Turkey without prior approval from other members of the caretaker government.
However Shiite leaders vowed continued support to Mr Jaafari calling it an internal affair of the Alliance and the decision to change the candidate was the Shiite’s prerogative.
“Even if other groups come to us with requests, we will not even discuss it,” said Shiite transportation minister Salam al-Maliki.
Iraq’s new parliament was elected in mid-December, but negotiations have been going on for weeks with little progress on setting up a government of national unity.