The announcement came as Hollywood actress Angelina Jolie urged foreign ministers at the G8 in London to boost efforts to bring wartime sex offenders to justice.
Foreign Secretary William Hague, speaking at the conference, said the commitment of resources was necessary to “end the treatment of rape and sexual violence as a secondary issue and to put women and women’s rights front and centre in conflict resolution”.
Half of the UK’s money will come from the Foreign Office, while the other half will come from the Department for International Development.
The UK’s pledge is part of a £23m package from the G8 nations. Mr Hague said: “We need to shrink and eradicate safe havens for those responsible for war-zone rape and this is a step towards doing that.”
Part of the funding would go into training the military to respond to conflict sexual violence. That training would be extended to peacekeeping groups of other nations, he said.
Speaking after a meeting that included US secretary of state John Kerry and Russian foreign minister Sergei Lavrov, Jolie, a goodwill ambassador for the United Nations High Commissioner for Refugees, said the world needed to do more to prevent such crimes. “Hundreds of thousands of women and children have been sexually assaulted, tortured or forced into sexual slavery in the wars of our generation,” she said, flanked by Zainab Hawa Bangura, UN Special Representative on Sexual Violence in Conflicts.
“Today, I believe their voices have been heard and that we finally have some hope to offer them.”
Geoffrey Dennis, chief executive of charity Care International UK, said diplomacy had to be followed through with action on the ground.
Mr Dennis, who advises Mr Hague on preventing sexual violence, said: “There will be no quick fix for the lawlessness and brutality in which these horrific crimes occur, but if today’s commitments result in more concerted action by G8 nations, that could help stem the violence.”