Angelina Jolie-Pitt said the rights of women should be placed at the heart of United Nations peacekeeping operations.
The Hollywood star and UN special envoy said allegations of abuse against women should be properly investigated and followed by prosecutions of those responsible.
She told a summit of ministers from around the world in London's Lancaster House that countries had to meet their commitments to peacekeeping missions and aid appeals.
The summit communique called for the UN to double the number of women in military and police contingents involved in peacekeeping operations by 2020 and promised a "zero tolerance" approach to sexual exploitation and abuse by troops.
Jolie-Pitt told ministers and dignitaries at the meeting: "The fact is that increasing the number of UN peacekeepers alone will not be enough to resolve the conflicts that we are experiencing.
"It has to be accompanied by a new way of conducting peacekeeping, one that has the rights and protection and involvement of women at its heart."
She added: "The signing of an agreement is actually the easy part.
"What is harder and what is much more important is implementation.
"We are living through a time of public disillusionment with commitments on paper that are not met in reality; with UN Security Council resolutions that are ignored, aid appeals that are only partially met and fail to address root causes and allegations of sexual misconduct that are not investigated or prosecuted.
"In my view, from my experience in the field, prosecutions around the world would mean more to the survivors of violence than any number of new Security Council resolutions."