BAGHDAD: Iraqi MPs failed on Wednesday to agree a new electoral law intended to establish more transparency for elections due in January because of a stalemate over Kirkuk, casting serious doubt on whether the poll can be held on schedule.

The decision to hand the issue over to a senior political council made up of Prime Minister Nuri al-Maliki, President Jalal Talabani and the leaders of major political parties is the latest in a series of delays to the law.

The "opinion of some political parties became more intransigent, and this made an agreement impossible," said parliament speaker Iyad al-Samarrai, adding that lawmakers would vote on the bill on Monday if the council came up with a proposal by Sunday.

"The subject became bigger than the parliament and there was no way to negotiate."

The delay was triggered by failed negotiations relating to oil-rich Kirkuk, an ethnically mixed province in northern Iraq that Kurdish leaders want incorporated into the autonomous Kurdistan region.

Kirkuk's Arab and Turkmen communities remain strongly opposed to the Kurdish ambitions, which also extend to parts of neighbouring provinces.

Article 140 of the constitution calls for a referendum to decide Kirkuk's fate but it has been put off at the recommendation of the United Nations.

Wrangling over the bill comes as US forces reduce their presence in Iraq and calls from both the UN and Washington for a speedy resolution of the issue.

On Tuesday, US President Barack Obama urged Iraq's parliament to end delays and pass the bill, which would decide whether ballot papers in next year's election will show candidates' names or only party titles.

Senior US commanders are watching election-related issues as they prepare for withdrawing around 70,000 American troops by the end of August 2010 under an agreement with Baghdad.

On Wednesday, UN special envoy to Iraq Ad Melkert urged MPs to approve the bill, saying further delays risked undermining the credibility of the election, the first national vote since the overthrow of dictator Saddam Hussein in the US-led invasion of 2003.

"Time is critical, and further delays in ratifying the amendment clarifications and the legal framework can adversely affect both the current electoral timeline, and ultimately the credibility of the electoral process," he said in a statement.

A vote was originally slated to be held on Thursday, but was delayed until Monday, and daily debates since then have so far proved fruitless.

Haidar al-Abadi, an MP in Maliki's Dawa party said the latest delay was a stain on parliament's reputation.

"Parliament today proved it is unable to legislate, and the parliament's presidency (the speaker and his two deputies) put the last nail in its (parliament's) coffin," by referring the issue to the senior council, he said.

This month, a parliamentary official told AFP that while several sitting MPs publicly supported an open voting system and called for the bill to be passed, they remained privately opposed because they feared losing their seats.

The electoral commission has said it requires 90 days to organise the polls. With elections scheduled for January 16, the bill should have been passed by October 19.

Constitutionally, the vote is required to be held by January 31.

The failure to agree new legislation has left open the prospect that the old law, which advocated a closed system, could be used in the January polls.

But Iraq's top Shiite cleric Grand Ayatollah Ali Husseini al-Sistani, whose stature dwarfs that of any of the country's politicians, has expressed his opposition to that system.

Earlier this month, MPs moved to retain the more opaque voting system used in 2005 but the move triggered an intervention by Sistani, and sparked widescale protests.

The more open system advocated by Sistani was used in provincial elections in January that saw Maliki's allies take a majority of votes in nine of Iraq's 10 Shiite-majority provinces, including the capital Baghdad.