The board of Iraq's electoral commission resigned en masse on Tuesday in protest at political and judicial "interference", throwing a general election due next month into disarray.

The sudden decision comes with doubts already swirling over whether the Independent High Electoral Commission (IHEC) could organise polling nationwide on April 30 with anti-government fighters in control of a city on Baghdad's doorstep.

Much is at stake in the election, as Prime Minister Nuri al-Maliki bids for a third term with his security credentials thrown into question by a surge in violence to levels not seen since 2008, with 37 more people killed on Tuesday.

The nine-member IHEC board handed in its resignation in protest at what it said were conflicting rulings from parliament and the judiciary on the barring of would-be candidates for the election.

"The commission is today caught between two authorities -- the legislative and the judicial -- and the two have issued contradictory decisions," IHEC spokesman Safa al-Mussawi told AFP.

"We are stuck in the middle, so we have decided to resign."

An aide to IHEC chairman Sarbat Rashid told AFP that he backed the decision. An IHEC board member, who did not want to be identified, said the same.

"They are very frustrated with this judicial panel for the elections... excluding candidates," a diplomatic source said on condition of anonymity.

"They are very unhappy with judicial interference, with political interference."

The resignations still have to be approved by parliament, the source added.

Several candidates have been barred in recent weeks on the grounds of alleged ties to now executed dictator Saddam Hussein's Baath party.

But a greater source of frustration for the IHEC board has been the exclusion of scores of hopefuls on the basis of what critics say is a vague provision in Iraq's electoral law that requires that parliamentary hopefuls be "of good reputation".

Those barred, who include former finance minister Rafa al-Essawi, a Maliki opponent, have no obvious avenue of appeal against the judicial panel's decision.

Parliament has meanwhile reportedly ruled that IHEC must not bar any candidates unless they have criminal convictions, a decision the IHEC spokesman said was at odds with that of the judicial panel.

'Message not to interfere'

It was not immediately clear what impact the resignation of the IHEC board would have on next month's election, which all major parties are agreed must take place on schedule.

One analyst said the resignations themselves were unlikely to disrupt the timetable.

"The election will go ahead on time, whatever the situation, because there is no way parliament will approve these resignations," said Ihsan al-Shammari, a politics professor at Baghdad University.

"The resignations are a message to the two authorities... not to interfere in their work," he said.

"The conflict between the two authorities has put pressure on IHEC ... and forced them to present their resignations."

The looming vote has been a factor in the rising bloodshed in recent months, analysts and diplomats say.

Maliki and other Shiite political leaders have been determined to be seen to take a hard line against militants, rather than reach out to the Sunni Arab minority in a bid to undercut long-term support for militancy.

But despite widely trumpeted operations against insurgents, bloodletting has continued, with more than 400 people killed so far this month, and upwards of 2,100 this year, according to an AFP tally.

On Tuesday alone, 37 people were killed nationwide, including eight who were killed in a gun attack on an army patrol and 15 others who were killed in car bombs in and around the capital.

The April 30 poll is also seen as opportunity to break years of political deadlock between Maliki and his opponents, which has resulted in little significant legislation being passed.