Baghdad - The Iraqi parliament is expected to choose a new speaker in a run-off vote on Thursday after lawmakers failed on Wednesday to end an impasse that has paralysed the assembly since late December.

Iraqi law gives Sunni lawmakers the responsibility of nominating the speaker of the parliament, but Sunni parties again failed to agree on a nominee Wednesday, despite increasing pressure from the rest of the Iraqi government to end the dispute.

"We had hoped to reach an agreement among the factions on a single candidate," deputy speaker Khalid al-Attiya told reporters on Wednesday.

"But the National Accord (the main Sunni party) had difficulty choosing one. So we decided to let those who wanted to run to do so," the deputy speaker said.

Ayad al-Samarai, an outspoken opponent of Prime Minister Nuri al-Maliki from the Iraqi Islamic Party, is the front-runner for the position.

On Wednesday, Ezzat al-Shahbandar, a member of parliament for former prime minister Iyad Allawi's the Iraqi National List, told London's pan-Arab daily al-Sharq al-Awsat that the new prime minister "would strongly oppose al-Samarai's appointment."

"Ayad Al Samarrai is part of a coalition between the Kurds and the Supreme Council (a leading Shiite party), and other powers, who are openly seeking to limit al-Maliki's role, or even remove him from power through a parliamentary vote of no-confidence in his government," al-Shahbandar told the daily.

The speaker's post has been vacant since December 23, when the former speaker, Mashud Mashhadani, quit after a chaotic debate over whether the parliament should pass a resolution asking for the release of Montazer al-Zaidi, the 30-year-old Iraqi television journalist who had thrown his shoes at former US president George W Bush a week before.

Al-Zaidi's trial was adjourned until March 12 after a brief session on Thursday at Baghdad's Central Criminal Court. (dpa)