KABUL: Afghanistan's preliminary presidential election result has been delayed by two days due to fraud investigations and will now be released on Saturday, officials said Wednesday as they vowed to sift out fake votes.

Partial results from the April 5 election to succeed President Hamid Karzai have already been released, with former foreign minister Abdullah Abdullah ahead of his main rival Ashraf Ghani after half of the ballots were counted.

Hundreds of serious fraud allegations are being probed in an attempt to ensure a cleaner election than in 2009, when Karzai retained power in a vote marred by rampant cheating.

“The IEC is conducting thorough investigations of all irregularities,” the Independent Election Commission said in a press release.

“While these investigations have delayed the process slightly, they are critical to the accuracy and integrity of final results.”

The latest partial results put Abdullah in the lead with 44.4 per cent followed by former World Bank economist Ghani on 33.2 per cent.

If no candidate gains more than 50 per cent, a second-round election between the two leading names is tentatively scheduled for May 28.

Saturday's preliminary result will be followed by the final official result on May 14, after a period for adjudication of complaints.

The United Nations mission in Afghanistan on Wednesday pushed the IEC and the Independent Electoral Complaints Commission (IECC) to do more to demonstrate that the prolonged count was being conducted fairly.

“The Afghan electoral institutions should be commended for their efforts to make the electoral process more transparent than ever before and be encouraged to take further proactive steps in this direction,” said Jan Kubis, head of UNAMA.

Overall turnout is set to be nearly seven million voters from an estimated electorate of 13.5 million people — far above the 2009 turnout.

The incoming president will have to oversee the fight against a resilient Taliban insurgency as US-led combat troops leave Afghanistan this year, and must also strengthen an economy reliant on declining aid money.

Eight candidates ran in the election, with polling day hailed a success by Afghan officials and foreign allies as the Taliban failed to launch a major attack despite threats to disrupt the vote.