By Frank Nyakairu

KAMPALA (Reuters) - Uganda said on Friday it would for the first time set prices for any food the government purchases to fight corruption and collusion, but the policy will not affect private businesses.

"As a way of curbing corruption, we have come up with minimum prices for all government suppliers because of increasing commodity prices," said Dora Egunyu, spokeswoman of Uganda Public Procurement and Disposal of Assets.

"We have informed government agencies and auditing firms not to procure commodities above or below the estimated price levels."

Prices of most food items, including those locally produced, have more than doubled since the start of 2008, raising fears that the country could be headed for a food crisis.

Food shortages are worse in sub-Saharan Africa because per-capita food production has fallen relentlessly in recent years. The most-affected countries include Ethiopia, Zimbabwe, Malawi, Eritrea, Zambia, Niger, Djibouti and Sudan.

The World Food Programme has carried out more emergency operations in sub-Saharan Africa than elsewhere.

But the Uganda government is reluctant to fix prices in free markets with inflation standing at over 9 percent.

"For the government to come in and stop these soaring prices distorts the economy, yet we don't want to go back to where we were many years ago," Finance Minister Ezra Suruma told Uganda's parliament last week.