AFP - Iraqi clerics, both Shiite and Sunni, called on members of parliament on Friday to end a protracted deadlock over a key election law that threatens to delay polls scheduled for January.

A representative of Shiite spiritual leader, Grand Ayatollah Ali al-Sistani, warned of the security implications of any postponement following two massive bombings which killed 153 people in central Baghdad last Sunday.

"The current period is very sensitive, and terrorist forces are working to weaken people's confidence in the government and political parties," Sheikh Abdul Mahdi al-Karbalai told worshippers at his mosque in the central shrine city of Karbala.

"The time left to organise elections has become shorter -- they must take place on time because holding them on their current date is a democratic and constitutional principle.

"Delaying the elections will have dangerous effects on security," he warned.

A Sunni cleric in the southern port city of Basra delivered a similar message. It was echoed by Shiite clerics from the radical faction of Moqtada Sadr in Baghdad and from the Supreme Iraqi Islamic Council in the shrine city of Najaf.

Stalemate over the bill has sparked concern that the polls, scheduled for January 16, will have to be delayed because electoral authorities will not have enough time to organise them.

The latest attempt to put the draft electoral law to a vote failed on Thursday, when parliament failed to reach a quorum because Kurdish MPs stayed away amid a long-running dispute over the northern oil province of Kirkuk.

The impasse comes despite intense lobbying from both the United Nations and the United States, and pressure from Prime Minister Nuri al-Maliki.

Karbalai also sharply criticised the government over Sunday's twin suicide attacks at the justice ministry and the Baghdad provincial government offices, which came just two months after similar attacks killed around 100 people at the finance and foreign ministries.

"With insurgents having repeated the same bombings, with the same style and in the same secure area, we have to review the security plan that has been implemented in Baghdad," he said.

"I demand immediate and urgent checks for the reasons that led to the bombings."

Security remains tight in Baghdad, with several roads closed off, and stringent checks at multiple checkpoints across the capital.

More than 60 members of the Iraqi security forces have been arrested in connection with the attacks, and the prime minister and his interior and defence ministers are to face questions in parliament.

Baghdad governor Salah Abdul Razzaq has called for both Interior Minister Jawad al-Bolani and Baghdad Operations Command chief Lieutenant General Abboud Qanbar to be sacked.