BAGHDAD, Iraq, Sept. 22 - Grand Ayatollah Ali al-Husseini al-Sistani, the nation's most powerful Shiite leader, is growing increasingly concerned that nationwide elections could be delayed, his aides said, and has even threatened to withdraw his support for the elections unless changes are made to increase the representation of Shiites, according to one Iraqi source close to him.
Aides to Ayatollah Sistani contacted Lakhdar Brahimi of Algeria, the United Nations adviser who brokered the agreement to hold the elections, planned for January, to express concern that they would be delayed, according to Hamid Khaffaf, one of Ayatollah Sistani's top aides.
Another source close to the electoral negotiations said Ayatollah Sistani had asked Mr. Brahimi to return to Iraq to try to address his concerns. Mr. Khaffaf declined to discuss details of the conversation.
In New York, Mr. Brahimi's aides said only that he had not spoken recently to Ayatollah Sistani. The United Nations special representative to Iraq, Ashraf Jehangir Qazi of Pakistan, could not be reached for comment.
According to people with knowledge of the talks, Ayatollah Sistani is concerned that the nascent democratic process here is falling under the control of a handful of the largest political parties, which cooperated with the American occupation and are comprised largely of exiles.
In particular, these sources say, Ayatollah Sistani is worried about discussions now under way among those parties to form a single ticket for the elections, thus limiting the choices of voters and smothering smaller political parties.
Ayatollah Sistani, who earlier this year sent tens of thousands of Iraqis into the streets to demand early elections, is said to be worried that a "consensus list" of candidates from the larger political parties would artificially limit the power of the Shiites, who form a majority in the country.
Under an agreement reached among exile groups in the early 1990's, the Shiites were said to make up about 55 percent of the population. Ayatollah Sistani, the sources say, believes the Shiite population has swelled since then and therefore would be underrepresented on any list based on a 55 percent figure.
Ayatollah Sistani also expressed concerns that the Iraqi government, possibly under American pressure, would postpone the elections on the pretext that the anarchical conditions that prevail over parts of the country would make the results illegitimate, the sources said.
According to an Iraqi close to Ayatollah Sistani who spoke at length with him last weekend, the ayatollah is so upset about the prospect that the Shiites might be underrepresented that he is prepared to withdraw his support for the elections if his concerns are not addressed. It is unclear, however, what specific demands he has made.
"If he sees that what this is leading to is unfair and unfree elections, then he will not take part in it,'' the Iraqi said. "He will declare the elections to be illegitimate."
The activity by Ayatollah Sistani represents a reassertion of his efforts to ensure that the country's long-suppressed Shiite Arabs translate their majority status into political power. In the months since the Americans toppled the regime of Saddam Hussein, Ayatollah Sistani has largely stayed away from engaging in the minutiae of partisan politics, but he has aggressively pushed the Americans, the United Nations and the Iraqi government to hold democratic elections as soon as possible.
The prospect of a boycott by Ayatollah Sistani could have severe consequences. The grand ayatollah, the senior cleric among the Shiite religious hierarchy, commands vast respect among ordinary Iraqis, many of whom could be counted on to give serious consideration to a pronouncement by him about the elections. An association of Sunni clerics has already announced that they will boycott the election.
Ayatollah Sistani's concerns also reflect a certain ambivalence regarding the presence of foreign forces in the country and the influence of international organizations like the United Nations. In the months since the Americans toppled Mr. Hussein, Ayatollah Sistani has declared a wish to end the American presence, but he has not told Iraqis to oppose it aggressively.
His concerns come at a time of growing uncertainty about the feasibility of holding elections here in January, with a guerrilla insurgency raging across much of Sunni-dominated areas north and west of Baghdad. Last week, Secretary General Kofi Annan said he doubted whether legitimate elections could be carried out in the current environment. Some United Nations officials in Baghdad, however, have said they believe elections can go forward.
American commanders say they intend to bring many of the most restive areas, including Falluja, under control by the end of the year, by force if necessary.
In recent weeks, the leaders of the major Iraqi parties have been negotiating the possibility of forming a unified ticket for the elections.
Under the electoral system, drawn up by the United Nations, voters will select not individual candidates but lists, whose members will take a number of seats in the National Assembly roughly proportional to the shares of the votes their parties receive.
While many Iraqi leaders envisioned that each party would put forward its own list for the election, the negotiations among the larger parties are driving at consolidating all of the candidates onto a single slate. Party leaders involved in the negotiations say such a ticket would be conducive to national unity in a time of great distress.
"The goal is to have a united front,'' said Adil Abdul Mahdi, the Iraqi finance minister and a member of the Supreme Council for the Islamic Revolution in Iraq, a leading Shiite party. "We think that would be better for the unity of the country."
It was unclear late Wednesday precisely what Ayatollah Sistani sought from Mr. Brahimi or others at the United Nations. Mr. Khaffaf declined to discuss what Ayatollah Sistani would like Mr. Brahimi to do, other than to say, "The most important thing now is to hold the election at the specified time.''
As concerned as Ayatollah Sistani is about early elections, he appears to be equally worried that the democratic process may be usurped by the well-financed major parties, nearly all of which flourished in exile and cooperated with the American occupation. These parties include the Iraqi National Accord, which is headed by the prime minister, Ayad Allawi; the Supreme Council for the Islamic Revolution in Iraq, known as Sciri; the Dawa Party; the Iraqi National Congress; the Kurdish Democratic Party, and the Patriotic Union of Kurdistan.
Dawa and Sciri are Shiite-dominated political parties; the National Accord and the National Congress are of mixed religion and ethnicity.
All six of these parties are dominated by exiles, and together they formed the core of the external opposition to Saddam Hussein. Each was represented on the Iraqi Governing Council, the American-approved advisory board that served during the 15 months of military occupation.
"Ayatollah Sistani's concern is that the elections are being controlled and managed by the political parties that took part in the government,'' said the source close to Ayatollah Sistani.
Similar complaints arose last month during the gathering that was called to choose a National Conference, which is now advising the government.