Kai Eide, the UN special representative to Afghanistan, says next month's presidential runoff vote "is not going to be perfect".

But his admission comes after the sacking of Peter Galbraith, the US special representative in Afghanistan and subordinate of Eide, who was fired by the UN secretary-general for publicly denouncing widespread corruption during the previous ballot.

Eide has since acknowledged that hundreds of thousands of votes were cast fraudulently on August 20.

In an exclusive interview, Imran Garda asks Eide about the runoff on November 7 and whether the Norwegian diplomat owes Galbraith an apology.