The Iraqi Islamic party, a mainstream political movement representing the minority Sunni Muslim community, announced Monday it would boycott next month's landmark elections.
"We are obliged to pull out," party chief Mohsen Abdel Hamid told reporters in Baghdad, saying the decision was motivated by the refusal of authorities to postpone elections for six months to ensure broader participation.
"Our party asked on December 5 that elections be delayed for six months using reasonable arguments," he said referring to the worsening security situation in the country in the run-up to the January 30 vote.
"The authorities concerned have refused to hear the voice of reason."
The party had previously presented an election list of 275 names, a number equal to the seats that are up for grabs in the national assembly.
Abdel Hamid was a member of the defunct Governing Council that was put in place after the fall of Saddam Hussein's regime in April 2003.
He has been a critic of the use of excessive force against insurgents in Sunni-dominated areas like the former rebel stronghold of Fallujah west of Baghdad.
The Sunni religious establishment led by the influential Committee of Muslim Scholars along with other Sunni civic and political figures announced in mid-November that it would not take part in the elections.
Abdel Hamid left the door open for a change of heart saying his party would reconsider its decision and take part in the elections if certain conditions are met regarding an improvement in the security situation, more public awareness of the elections and a more transparent role for the independent electoral commission, charged with overseeing the process.
"The security situation is very dangerous, there are six provinces (out of 18) where elections cannot take place in a normal fashion, elections cannot be credible without the participation of all the provinces" he said.
"People do not understand the political process and need at least six months to be able to do that."
Iraqi Foreign Minister Hoshyar Zebari said in an interview with Chinese media Monday that voting could be delayed in some parts of the country due to the fragile security situation.
"Elections in dangerous regions like Mosul and around Baghdad may be delayed so that we can concentrate our security resources to destroy opponents' capacity to target and intimidate people," the foreign minister told Xinhua news agency after a four-day visit to China.
The long-oppressed Shiites, who make up about 60 percent of the population, are expected to overturn decades of Sunni-dominated rule in the vote, which could worsen the Sunni insurgency raging in Iraq.
Iraqis are to vote for a 275-member national assembly that would draft a constitution to replace the country's interim law passed by the now defunct US-led occupation authority, ahead of fresh elections.
They will also elect provincial councils.
With the pullout of the Iraqi Islamic party, the Sunni field would essentially be represented by the party of senior politician Adnan Pachachi and some independent figures.
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