Kurdish opposition groups complained of widespread violations in Saturday's Kurdistan elections but Iraq's electoral commission said voting was largely sound, Reuters reported.
Results of the parliamentary and presidential polls in the largely autonomous Kurdish region in Iraq's north are expected to take at least one or two days.
The election is unlikely to alter radically the dominance of the two powerful political parties in the region or put an end to a feud between Kurds and the Arab-led government in Baghdad over contested territory and control of vast oil resources.
Kurdish President Masoud Barzani, a former guerrilla leader, looks certain to defeat five rivals.
The Change list, headed by independent Noshirwan Mustafa, said the authorities had executed a "premeditated plan to change the results for its own benefit."
"In the afternoon a campaign of violations began on the orders of the officials on the ground of the party in authority in all towns," the Reform and Services opposition list said in a statement late on Saturday.
The region's ruling parties -- the Kurdish Democratic Party (KDP), led by Barzani, and the Democratic Union of Kurdistan (PUK) of Iraqi President Jalal Talabani, a Kurd -- ran jointly against more than 20 alliances of smaller parties.
Opposition complaints included voters being allowed to cast ballots without identification, the blocking of polling stations to opposition observers and campaigning after the deadline.
Iraq's Independent High Electoral Commission (IHEC) said it would investigate officially submitted complaints of election violations, but told reporters late on Saturday the vote had been largely violation-free.
However, it did say Barzani had broken a campaign deadline rule by speaking to reporters after voting.
"This is not important, it was a very simple matter and has no effect on the elections," said IHEC's Qasim al-Sachet.
Jabbar Yawar, a senior KDP member, dismissed complaints of poll irregularities. "We reject this, if there were violations, then they can submit an official complaint," he said.
Abdilselam Berwari, head of the KDP Political Studies Center, said the complaints were a case of sour grapes.
"Our response is that we have expected the loser would not be so ready psychologically to accept defeat."
Turnout for the elections was relatively high, at 78.5 percent across Kurdistan, the electoral commission said.