The change will mean British aid money being used to fund human rights training for soldiers in developing countries.
In a speech on how the elimination of poverty can be linked to reform of military and police forces, Ms Short will set out a range of initiatives planned by her department, by the Foreign Office and by the Ministry of Defence.
Action to reduce the number of children fighting in wars will be taken through the United Nations and other international bodies. Programmes will be set up to stop the proliferation of small arms, which are available in enormous numbers in Africa.
More human rights training will be provided by the Department of International Development.
The department intends to ensure armies are fully under the control of civilian governments. It also wants to discourage excessive military spending as well as helping to support peace-keeping efforts in countries that have been hit by wars.
"It is the poor who are most vulnerable to being pushed around by ill- trained military and corrupt policemen. Getting security sectors to become more consistent with development is an important objective," one official said.
The foreign affairs think-tank Saferworld welcomed the move but said other government departments might not be as keen as Ms Short's team on disarmament.