BAGHDAD, Iraq – A leading Shiite candidate to become the next prime minister, Vice President Adil Abdul-Mahdi, said yesterday that Iraq may not have a new government until April if political and sectarian groups cannot set aside their differences.

A broad-based coalition government including Shiites, Kurds, and Sunni Arabs is the only way to defeat the insurgency, Mr. Abdul-Mahdi told the Associated Press in an interview at his home along the banks of the Tigris River.

“The future government, I think, will be a national unity government. This is a must. It is not something that only the results of the elections can decide. It is a political necessity, and all parties agree on that,” Mr. Abdul-Mahdi said.

The 63-year-old former exile’s remarks reflect the desire of many Shiites, especially politically moderate Islamists, to make the government more inclusive and representative in an effort to stop the daily bloodshed that ravages Iraq.

Mr. Abdul-Mahdi, who served as finance minister in Iraq’s first interim government, said the country’s political parties have to show flexibility if they want to form a government quickly.

“If we are flexible with our requests, then we can see a government in a very short period. But if we are reluctant, rigid, then this might take a while, maybe two months, three months,” he said. “We are hoping that all parties will be flexible and they will be moderate in their requests, practical in seeing things, looking at the future and not sticking to their pasts or the present.”

There were indications that the three main parties to emerge from the December 15 parliamentary elections – the Shiite United Iraqi Alliance, the Sunni Arab Iraqi Accordance Front, and the Kurdish coalition – were making significant headway in forming a coalition government ahead of the release of final results.

Leaders of the Accordance Front agreed Monday for the first time on the broad outlines for such a government during an unprecedented trip north to the Kurds.

Mr. Abdul-Mahdi said “theoretically we are very close” to forming a government, but it could take some time before final results are certified.

Some smaller Sunni Arab groups and secular parties are claiming widespread election fraud and have threatened to boycott the 275-member parliament if the elections are not rerun in some provinces including Baghdad.

Although the United Nations has endorsed the elections as credible, those groups want an international assessment team to inspect about 1,500 complaints thoroughly. The team began its work on Monday. Final results were to be released this week, but election officials said yesterday they may take two weeks.

Mr. Abdul-Mahdi said the process could last longer.

“They will not be announced until next week. Then there will be a period of verification and ratification,” he said. If there are appeals, “then it will take another two weeks.”

But Mr. Abdul-Mahdi said the real delays in forming a new government could appear when “we come to the real discussion of posts and key posts.”

One key post, that of prime minister, could go to the soft-spoken Mr. Abdul-Mahdi, the son of a respected Shiite cleric who was a Cabinet minister in Iraq’s monarchy. Trained as an economist, he left Iraq in 1969 for exile in France after being arrested, tortured, and jailed by the Baath party. In his youth, Mr. Abdul-Mahdi dabbled with Baathism and Maoism before adopting the Islamic-style democracy he now favors.

Mr. Abdul-Mahdi is currently a leading member of the powerful Shiite Supreme Council for the Islamic Revolution in Iraq, one of two major Islamic groups making up the United Iraqi Alliance, the religious Shiite political organization that dominates Iraq.

The other candidate for the country’s top job to emerge from the governing Shiite alliance is the incumbent, Prime Minister al-Jaafari, who heads the conservative Islamic Dawa party.