Election officials pored over votes from Afghanistan's parliamentary poll on Sunday, but sifting through fraud complaints and waiting for results from the remotest areas will delay even preliminary results for weeks.

Some areas have started sending checked ballot boxes back to Kabul, the Independent Election Commission (IEC) told Reuters the morning after the poll, which Afghan officials hailed as a success despite attacks, low turnout and extensive cheating.   

The election was being closely watched in Washington ahead of US President Barack Obama's planned war strategy review in December, which will likely examine the pace and scale of US troop withdrawals after nine years of war.

A flawed poll would weigh on Obama when his administration faces mid-term Congressional elections in November amid sagging public support for the war, with violence at its worst since the Taliban were ousted in 2001.

Around one million fewer votes were cast this year than in a presidential poll last year, 14 people died in attacks, and reports of ballot-stuffing, repeat voting, vote buying and other fraud came in from across the country.

The challenges meant many observers were circumspect in assessing the poll, a key test of government credibility after the presidential election was tarnished by widespread fraud.   

"The results and quality of the election will not be immediately evident," the US embassy in Kabul said in a statement after voting ended, adding it would support election officials tallying results and tackling fraud.

The Free and Fair Election Foundation of Afghanistan reported "extensive irregularities" ranging from the destruction of polling centres to ballot stuffing, erratic opening and closing times of polls, and interference by candidates.   

In a statement on its website, it called on the IEC "to ensure the integrity of the rest of the electoral process".

United Nations Secretary General Ban Ki-moon asked for patience as authorities completed the electoral process, which Afghanistan's poll watchdog had warned would be "disputatious".

It will not be clear for several weeks who among the almost 2,500 candidates have won the 249 seats in the wolesi jirga, or lower house. Preliminary results are due to be published on Oct. 8 at the earliest, with final results not out before Oct 30.

"There are various reasons why it takes so long to do all of this. One is the transfer of ballot boxes from remote areas to Kabul, and putting the results on the data base," said an IEC official who declined to be named because he is not authorised to speak to the media.

"Then we will have to give time to the Electoral Complaints Commission to register and verify people's complaints," he said.   

The election was only the country's second chance to choose a parliament since the ouster of the Taliban by US-backed Afghan forces in 2001.   

In Kabul, some of those who had fought one of the toughest races in the country were downbeat. "The election without any doubt was held under a situation whereby there was no psychological or physical reassurance. It was held under conditions of intimidation, pressure and fraud," said Musa Fariwar, a professor of law at Kabul University.

"I was a candidate for Kabul and witnessed fraud." -Reuters