KABUL - An election official warned Thursday that Afghanistan has a narrow two-week window in October to hold any presidential runoff before winter snows arrive -- a somber reminder of how minor delays could leave a power vacuum well into next year.

Preliminary results from Afghanistan's Aug. 20 vote show President Hamid Karzai winning outright with 54.6 per cent. But if enough votes are found to be fraudulent from an election mired in allegations of ballot stuffing and voter coercion, Karzai could dip below the 50 per cent threshold needed to avoid a runoff with challenger Abdullah Abdullah.

The uncertainty puts the government on hold as Taliban attacks spike and threatens the credibility of the administration at home and abroad. The main question at this point is how much misconduct is acceptable to both Afghans and an international community skeptical of sending troops in support of a tainted government.

A top official from Afghanistan's election commission said members were committed to holding a runoff vote if called for by fraud investigations and the ordered recounts and audits.

"It should be according to international standards," said Daoud Ali Najafi, the chief electoral officer of the Afghan election commission. Najafi promised that they would be ready for a runoff as soon as the third week in October, but that pushing it past the end of that month would be unrealistic because of the onset of winter.

Official statements from the United Nations and the Obama administration have called for a thorough investigation into all claims and to rigorously root out fraudulent ballots.

Yet there appears to be disagreement on how to handle the issue of fraud within the UN, at least, where the top American official at the UN mission here went on leave to Vermont earlier this month after a differing with his boss over the process of dealing with suspect votes.

And Australia's prime minister said on Sunday that Afghanistan should not be judged like "a perfect Jeffersonian democracy."

"This is not going to be a perfect outcome, let's just all accept that for reality, rather than pretend that it's something other than it could ever have been," Prime Minister Kevin Rudd said on CNN.

A runoff has seemed increasingly likely in recent weeks as independent analyses of the preliminary results showed more and more indications of fraud. The European Union monitoring team said about 1.1 million of Karzai's 3.1 million votes were questionable. If even a third of those suspect ballots were thrown out, Karzai's tally would fall below 50 per cent.

Najafi said the election must be held before the end of October, when entire provinces get closed down by winter snows, leaving just a two-week window for the runoff.

"The first week of November, it's a very difficult time" because of blocked roads and inaccessible villages in the north, Najafi said.

In the last presidential election, on Oct. 9, 2004, heavy snow in the Panjshir valley just north of Kabul meant some ballot boxes nearly weren't retrieved, Najafi said.

Najafi said he hopes final results will be known with enough time to hold any runoff this fall, but said it is not worth compromising the integrity of the vote to rush the process. If a runoff is called too late to hold it this fall, Najafi said the commission would try to negotiate a solution with all parties. He left the possibility vague, but some people involved in the process have hinted at either an interim government or some sort of power-sharing deal.

Many of the debates about a second-round vote have been about whether it would just rubber stamp Karzai's win, or if longshot contender Abdullah, a former foreign minister, could pull enough support from the 30-odd other candidates to unseat him. Abdullah has 27.8 per cent in preliminary results.

Some Karzai backers say that the president is sure to win in a second round, and that the exercise would only force Afghans to endanger themselves for no reason.

Mohammed Mohaqeq, a leader in the Hazara ethnic community who came in third in the 2004 election but backed Karzai in the most recent poll, predicted turnout would be so low in any second round that it would add no credibility to Karzai's win. Taliban threats and violence on election day dampened turnout to about 39 per cent.

"The people don't want those threats again, and they don't want that day of violence again," Mohaqeq said.