A Canadian Army officer charged with killing a wounded and unarmed Afghan insurgent last October will face a court-martial, the Canadian Defense Department said.

Captain Robert Semrau was arrested on 31 December on charges of second-degree murder before being placed under conditional release a week later.

According to court documents, 35-year-old Semrau was heading a small group of Canadian soldiers in Afghanistan's Helmand province when it was ambushed by Taliban fighters.

After beating back the insurgents with the help of a US attack helicopter, the Canadians came across a seriously wounded Taliban fighter, who was disarmed and judged too injured to provide medical aid.

The court papers found that Semrau was the only person near the wounded insurgent when two gunshots were heard. At least one witness said they saw Semrau fire his weapon on the wounded man.

Upon his arrest the Canadian Forces National Investigation Service (CFNIS) said it charged Semrau with one count of second-degree murder for "shooting, with intent to kill, an unarmed male person."

Canada has nearly 2800 troops based in Afghanistan, mainly stationed in Kandahar province. Since their mission in the country began in seven years ago, 131 Canadian soldiers have died in the conflict.