Iraqi Prime Minister Haider al-Abadi said on Thursday that allegations of fraud in national elections held last week will be investigated, according to a statement from his office.
The electoral list of Moqtada al-Sadr, a populist Shi'ite cleric, unexpectedly won the biggest number of seats in the May 12 ballot.
The fraud claims have centred on the city of Kirkuk - although there have been reports of irregularities in multiple provinces - and focused on the tabulation system in electronic voting machines that were used for the first time during the election.
A special committee appointed by the cabinet will investigate the allegations, Abadi's office said.
Some candidates have also expressed concerns about voter intimidation and reports of chaotic distribution of ID cards, which they claim disenfranchised hundreds of thousands of people.
Following several days of complaints - including a call for an investigation by the UN's senior envoy to Iraq, Jan Kubis - the country's electoral commission said on Monday it had invalidated ballots from 103 polling stations in five provinces.
The investigatory committee, which will include advisers from the security and intelligence sectors, will have access to all documents pertaining to the electoral process, including from the electoral commission.
The commission could not immediately be reached for comment.