The international development secretary will say that the world's security and stability is threatened by illicit sales.
"
Throughout the world thousands of people are killed each year and many more injured
"
Mike O'Brien
Ms Short is to urge representatives from 60 nations to implement tough new controls on small arms such as sub-machine guns and assault rifles.
The UK Government believes around 639m small arms are in circulation.
Comprehensive gun controls which would regulate their transfer and battle against the illegal small arms trade are needed, say ministers.
The purpose of the conference is to build consensus among countries that produce or export small arms and light weapon.
Controls
Ahead of the conference, Ms Short said: "Small arms and light weapons have wrought devastation and insecurity on the lives and livelihoods of people - particularly poor people - all over the world.
"They exacerbate conflict and crime and undermine development.
"At the UN in 2001, the international community agreed on the need to control the supply of both legal and illegal exports of weapons.
"Today's meeting brings together 60 nations to drive this agreement forward."
Foreign Office Minister Mike O'Brien is also due to address the conference.
Many deaths
He said that the UK Government is committed to "stemming the flood of small arms and preventing them getting into the hands of criminals and terrorists".
He will add: "Throughout the world thousands of people are killed each year and many more injured."
"Export controls are only a part of the answer; but they are an important one.
"This meeting can make a positive contribution to the launch of the global work needed to tighten controls on small arms, so that they only go to those with a legitimate use for them."
The two-day conference is being jointly hosted by the Foreign Office, the Ministry of Defence and the International Development department.