African Union commission chair Nkosazana Dlamini-Zuma, speaking at a press conference in Geneva on Monday, questioned whether it was right to second-guess Zimbabwe's courts.
Zimbabwe's Constitutional Court ordered Mugabe two weeks ago to hold the poll by the end of July, but Prime Minister Morgan Tsvangirai has rejected his rival's declaration, saying it was too early and accusing him of creating a political crisis.
On Saturday, Southern African leaders meeting at a summit in Mozambique told Zimbabwe to ask its courts to extend the deadline.
"The courts have said the elections must take place. And so do we listen to the courts? Or do we not listen to the courts? I thought a lot of you have always been talking to us about the rule of law and respect for the judiciary," Dlamini-Zuma said.
"So I don't know. The Zimbabweans must sort it out, whether they listen to the judiciary and go with what the judiciary has said, or whether they ignore it."
Mugabe used a presidential decree to bypass Parliament to fast-track changes to election laws and declare the voting date. His justice minister has denied any need for the media or security reforms that Tsvangirai's party says must be enacted before an election takes place.
The AU plans to send observers to monitor the election, Dlamini-Zuma said, adding that the most important question was whether the voting was free and fair.
Zimbabwe successfully held a referendum on its Constitution and she said she hoped that the election would be similarly peaceful.
"And of course their economy is also picking up, which is good, so we wish them the best, and if the elections go well I think it will augur well for Zimbabwe," she added.
SADC calls for delay
Meanwhile, Tsvangirai on Monday backed calls by the Southern African Development Community for Mugabe to delay crucial polls due by the end of July.
"We have to hold elections by October 31," Tsvangirai's spokesperson Luke Tamborinyoka said.
Zimbabwe's Constitutional Zourt last month ruled fresh polls have to be held by July 31, a date which Mugabe has backed, but Tsvangirai wants electoral reforms passed first and argues the law allows for three more months.
Mugabe's Zanu-PF and Tsvangirai's MDC parties have since 2009 been in an uneasy coalition formed in the aftermath of deadly post-election violence the previous year.
On Saturday, the 15-country Southern Africa Development Community urged Mugabe to request a delay from the constitutional court.
The bloc also urged the 89-year-old president to "undertake immediate measures to create a conducive environment for the holding of peaceful, credible, free and fair elections".
No date suggested
"SADC did not suggest a date. To us the date is subservient to the reforms. The reforms should come first and the latest we can have elections is by October 31," Tsvangirai's spokesperson said.
The prime minister argues that a July deadline will not allow for free and fair polls. He wants reforms in the media and security services, and says the voters' roll needs to be rid of ghost voters before the elections.
He has said he would veto the polls if reforms are not implemented but Mugabe has accused him of being afraid to lose.
"The other parties do not want elections, they are afraid of elections," Mugabe was quoted as saying in the state-owned Sunday Mail.
"They know they are going to lose and it's a sure case that they are going to lose." – Reuters, AFP