Prince Harry has been accused of being "arrogant and insensitive" after he talked of killing Taliban insurgents during his latest tour of Afghanistan.
The 28-year-old said in a series of media interviews that he took fighters "out of the game" during his 20-week posting.
Lindsey German, convenor of the Stop The War Coalition, said the comments were "crass" and asked how the Prince knew those he killed were members of the Taliban.
"In recent months many civilians have been killed by air strikes. This arrogant and insensitive attitude to killing Afghans, whoever they are, is hardly likely to win hearts and minds - a supposed aim of the war.
"Prince Harry returns to a life of idleness and luxury, unlike most soldiers who face unemployment, austerity and social problems," she said.
The Stop The War Coalition is finalising details of events next month to mark the 10th anniversary of the huge protests against going to war in Iraq.
CND general secretary Kate Hudson said: "After more than a decade of war, resulting in an unconscionable civilian death toll and a fractured country, it is unacceptable that the media only gives such high-profile coverage of this bloody and protracted conflict when it involves a member of the Royal Family.
"As we approach the 10-year anniversary of the invasion of Iraq, we should be reflecting on the catastrophic impact of our military interventions in the Middle East.
"Poring over the exploits of a royal in combat is a sad diversion from the deep, critical appraisal which should be taking place about the UK's devastating wars."