"This is very unfair to the Zimbabwean people. Because here is Mugabe, he is a factor. He is there. He leads a party that has been in government for over 20 years," Zuma told Reuters in an interview.
Zuma said the creation of a unity government where Mugabe and opposition leader Morgan Tsvangirai share power had begun Zimbabwe’s stabilisation, but it was only a starting point.
"You cannot say it has stabilised but it has entered a phase of stabilisation politically," Zuma said, adding that the unity government agreement, pushed by southern African leaders, "was the only option. There was nothing else".
Western powers, who accuse Mugabe of ruining the country and violating human rights, are reluctant to begin pouring in aid to repair the devastated economy while the veteran leader remains as head of state.
In the highest-level African criticism of this stance, Zuma said it was wrong to hold back aid.
"When there was an election, it is not as if not a single human being voted for Mugabe in Zimbabwe. He had a very big percentage himself. He has a sizeable support."
Western donors have made clear they will only provide a large aid package to help rebuild the country once economic reforms are in place.
Much will depend on whether Mugabe and Tsvangirai can work together after years of animosity. Any new power struggle that divides the new government could undermine efforts to win the confidence of donors and foreign investors.