Kai Eide, head of the UN mission in Afghanistan, centre, is flanked by French Ambassador Jean de Ponton d'Amecourt, left, and British Ambassador Mark Sedwill during Sunday's news conference in Kabul. ((Altaf Qadri/Associated Press))

The head of the United Nations mission in Afghanistan said Sunday there was "widespread fraud" in August's presidential election, but denied allegations he tried to cover up evidence of cheating on behalf of President Hamid Karzai.

Kai Eide was responding to accusations from his former deputy, Peter Galbraith, who was fired on Sept. 30 by UN Secretary General Ban Ki-moon due to the public dispute over how to deal with the fraud allegations.

The Norwegian diplomat refused to reveal any numbers showing the extent of fraud, saying "any specific figures would be speculative" before a recount is complete.

He would only say that irregularities have been discovered in some polling stations in the south and southeastern areas of Afghanistan.

Eide made the comments at a news conference in Kabul, where he appeared alongside ambassadors from the United States, France and Britain.

He referred to Galbraith's allegations as "personal  attacks" against his integrity, adding they have "affected the whole election process."

Election workers began a partial recount, 12 per cent of the ballot boxes, on Oct. 5. A final result is expected in the coming days.

Preliminary results released last month showed Karzai led the voting with 54.6 per cent, enough to avoid a run-off with second-place finisher Abdullah Abdullah, his former foreign minister.

But the recount and audit ordered by a UN-backed fraud panel could cut Karzai's votes below the 50 per cent threshold needed to win outright.

With files from The Associated Press