Meanwhile, Zimbabweans still await the results, with the opposition accusing Mugabe of withholding them while he plots how to keep power.
The octogenarian Mugabe has led Zimbabwe since independence in 1980.
Frazer was responding to questions about whether some kind of power-sharing agreement could resolve the impasse.
"We think in this situation we have a clear victor," she said. "Morgan Tsvangirai won and perhaps outright, at which point you don't need a government of national unity. You have to accept the result."
But she added: "There may need to be a political solution, a negotiated solution."