A wide-ranging review of the UK's overseas aid spending has concluded that cash being spent through the UN Food and Agriculture Organisation (FAO) is not getting the best results in poverty-hit nations and may be better used elsewhere.
With the Government under extreme pressure to justify increasing foreign help at a time of severe cuts to domestic services, Mr Mitchell will say the body will be bypassed unless it implements reforms.
Spiralling food prices across the world have been thrust further into the spotlight in recent weeks as one of the factors behind the popular uprisings across the Middle East.
The Department for International Development (DfID) said that the review - to be published on Tuesday - would result in four million more people being able to feed their families and help for an extra 10 million children in the developing world.
Projects to be prioritised include road-building in Mozambique to give better access to rural markets, creating 150,000 farming jobs for women in Sierra Leone and cash transfers to allow impoverished Zambians and Yemenis to buy food.
It will also go on "community nutrition services" in India - the most controversial country receiving aid.
Mr Mitchell has been forced to defend the UK's continued help to the country despite its own economy booming dramatically amid criticism from some Conservative MPs angry about the increased aid budget at the time of austerity measures at home.
The DfID said the review had highlighted the "strong" performance of the World Food Programme - which would now get regular funding alongside disaster cash to carry out prevention work, such as getting supplies in place ahead of monsoons.
It also recognised the "key role" that could be played by the FAO but found that its performance was "patchy, particularly at country level and that reforms need to be prioritised".