Clare Short, the International Development Secretary, will unveil controversial proposals to spend millions of pounds on reform of the third world military as part of the Government's drive to combat poverty.
Although she will acknowledge that development organisations have been reluctant to get involved with the security sector, she will argue that conflict prevention is crucial to improving the lives of the poor.
The announcement, which will be accompanied by a policy paper setting out specific proposals, follows increasing concern about corruption and human rights abuses by soldiers in some countries. Ministers also fear the growing power of rebel troops - like those who captured and killed eight westerners in Uganda last week.
It is likely to infuriate third world campaigners, who will argue that aid money should be concentrated on buying food for the poor, not retraining foreign troops. But ministers believe that the focus of international development must inevitably change to keep up with the real world.
Ms Short will publish a policy paper setting out how she believes the overseas aid budget could be used to improve foreign armies. Third world governments could be refused British money if they do not agree to reform their military structures or, if necessary, reduce spending on weapons.
The strategy has been drawn up jointly by the Department for International Development, the Foreign Office and the Ministry of Defence.
Ms Short's department will focus on work not directly related to military activities or weapons. For example, it will teach army officers about international human rights law, help demobilise armies in the wake of conflict, and campaign for the number of child soldiers to be reduced.
In her speech, the International Development Secretary will highlight human rights abuses carried out by troops and emphasise the danger of weapons falling into the hands of corrupt soldiers. She will argue that governments in many countries should be encouraged to spend money on food or education rather than weapons.
The aim will be to create security sectors around the world which are on an appropriate scale and properly accountable to democratic civilian authority.