PRETORIA (Reuters) - South Africa's central bank said on Tuesday the regional economic outlook remained positive, but that tensions over Zimbabwe's disputed presidential election posed a downside risk.

"Africa's economic outlook remains positive given the continued favourable commodity price outlook, regional macroeconomic stability, rising oil production and continued capital inflows," the South African Reserve Bank said in a bi-annual monetary policy review.

"The most important downside risks for growth in the region would comprise heightened risk aversion by investors as a result of the tensions flowing from the Zimbabwe elections," it said.

Electoral officials in Zimbabwe say the main opposition candidate defeated veteran President Robert Mugabe in the March 29 election, but failed to garner enough ballots to avoid a run-off.

The opposition Movement for Democratic Change insists that it won outright, and that Mugabe manipulated the result to cling to power.

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