Sunni MP Saleh al-Mutlak is reported to be one of those barred candidates
Iraq's election commission has barred almost 500 candidates from running in national elections on 7 March.
A committee that vets candidates says some of those banned had ties to the outlawed Baath party, once led by Saddam Hussein.
Those barred are believed to include prominent Sunni Arab politicians. The formal list of barred candidates has not been released.
There is a formal process through which barred candidates can appeal.
Defence Minister Abdulqadir al-Obeidi and the nationalist politician Saleh al-Mutlak are reported to be among the 499 candidates barred from standing in the parliamentary election on 7 March.
Mr Obeidi was intending to run as a candidate for Prime Minister Nouri Maliki's State of Law coalition.
Saleh al-Mutlak is an MP and heads the Iraqi Front for National Dialogue, which performed well in last years local elections in Sunni Arab areas.
Mr Mutlak, a former Baath party member, has formed an electoral alliance with other prominent Sunni politicians and the former Iraqi Prime Minister Iyad Allawi.
The decisions were partly made by the Justice and Accountability Commission, which is responsible for ensuring the outlawed Baath party does not make a comeback in Iraqi politics.
Some analysts have criticised the body and the election commission for its alleged partiality and ties to Shia religious parties.
The disqualifications might stoke up sectarian tensions. Many Sunni Arabs boycotted the last parliamentary election in 2005.
The 7 March election is regarded as a crucial test for Iraq's national reconciliation process and ahead of a planned US military withdrawal in stages.
President Obama has pledged to withdraw all US combat troops from Iraq by the end of August 2010 and the remainder by the end of 2011, subject to security conditions.