"So there it is, let the MDC [Movement for Democratic Change] reject it or accept it. We will continue to rule this country in the way we believe it should be ruled," Mugabe said.
The run-off has been reduced to a single-horse race after Morgan Tsvangirai, the leader of the opposition MDC, pulled out of the vote earlier in the week, complaining of intimidation and violence by supporters of Mugabe's Zanu-PF party.
A court in Zimbabwe has meanwhile granted bail to an opposition official who faces the death penalty after being charged with treason and vote rigging.
Tendai Biti, the secretary-general of the MDC was freed on Thursday.
"We have been granted bail by the high court and ordered to surrender one trillion Zimbabwean dollars [$90] with the clerk of courts as part of the bail conditions," Lewis Uriri, Biti's lawyer said.
"We've also been asked to surrender title deeds to his house and that he should report once a week to the police."
Tsvangirai had said on Wednesday that he was prepared to negotiate with the government of Mugabe, but that Biti's release would have to come before any talks.
"We are making this proposal, which Mugabe has the choice to accept or not, and I am sure that Zimbabweans want a negotiated way out of the crisis," he told Al Jazeera.
"Both parties [Zanu-PF and the MDC] must realise that this country is burning and the only way is to sit down and find a way out of it."
Tsvangirai's withdrawal has been followed by international calls for the 84-year-old president not to go ahead with the election unopposed.
Condoleezza Rice, the US secretary of state, warned Mugabe that were he to declare himself the victor on Friday the result would be seen as "illegitimate".
"Clearly, no run-off election that doesn't have the participation of opposition ... can be considered legitimate, no outcome can be considered legitimate," she said during a visit to Japan.
|Tsvangirai pulled out of the presidential
race earlier this week [AFP]
Leaders of the Southern African Development Community (SADC) said that the election should be delayed while Mugabe's government and the MDC hold talks.
"The political situation appears not to be permissive for holding the run-off elections in a manner that will be free and fair," Tomaz Augusto Salomao, chief of the 14-nation SADC, said on Wednesday.
South Africa said that a senior negotiator was in the Zimbabwean capital Harare discussing a range of option including a postponement of the vote.
However, Bright Matonga, Zimbabwe's deputy information minister, told Al Jazeera that there was no need for negotiations as Zimbabweans would make their choice at the ballot box.
"Tsvangirai should be out there campaigning. My president is addressing a massive rally in Chitungwiza, " he said. "Tsvangirai should be out here and he should not give conditions on President Mugabe."
Nelson Mandela, the former South African president, has meanwhile expressed concern over the Zimbabwean crisis and criticised what he said was a "tragic failure of leadership" in Zimbabwe.
"We look back at much human progress, but we sadly note so much failing as well," he said on a visit to the British capital London.
The MDC says that at least 80 of its supporters have been killed by Zanu-PF loyalists and another 200,000 people have been displaced in what it calls Mugabe's "campaign of intimidation" to deter people from voting.
Mugabe supporters have denied the allegations.
Hundreds of opposition supporters have taken shelter in the South African embassy in Harare saying that they fear attacks by Zanu-PF loyalists.