Iraq's parliament on Thursday voted to extend by three months the terms of nine members of the electoral commission, including its chief and a colleague detained last week on suspicion of corruption.

"The majority of the 197 MPs present voted to extend the mandate of the nine leaders of the IHEC in order to able to choose their replacements," Shiite MP Aziz al-Okaili told AFP, referring to the Independent High Electoral Commission.

"If during those three months the committee has not finished its work, a new extension will be necessary," he said.

Parliament had received applications from 7,300 candidates when the IHEC registration process closed last November, with a 22-member committee of experts reducing the number of people who fulfilled the criteria to 4,200 in February.

The committee must now interview 60 candidates and choose nine new officials who will have a four-year mandate, according to the United Nations, which is participating in their selection.

Thursday's vote follows the detention for three days last week of IHEC head Faraj al-Haidari and Karim al-Tamimi on suspicion of corruption, after a complaint filed by Hanan al-Fatlawi, an MP from Prime Minister Nuri al-Maliki's State of Law coalition.

Haidari's arrest has aggravated Iraq's political crisis, sparking condemnation from a number of leading Iraqi political factions, which accused Maliki of orchestrating a slide away from the electoral process and towards dictatorship.

The two men were released on bail on Sunday for 15 million Iraqi dinars ($12,500) each.

In an interview with AFP in the heavily fortified Green Zone following his release, Haidari said his and Tamimi's arrest "was not a good act, and does not serve the democratic political process."

"Insulting IHEC like that harms the political process as a whole, and endangers its independence, and the pressures on IHEC mean a retreat in the democratic political process and even a retreat in elections," he said.

Haidari, a Shiite Kurd, complained that the IHEC, which is responsible for organising all elections in Iraq, had been hit with a barrage of trivial court cases.

The terms of the current IHEC members was due to expire on April 28.