Australian Federal Police (AFP) raided the Sydney headquarters of the ABC over a series of stories that exposed unlawful killings and other misconduct by Australian soldiers in Afghanistan.

"This is a serious development and raises legitimate concerns over freedom of the press and proper public scrutiny of national security and Defence matters," said ABC managing director David Anderson.  "The ABC stands by its journalists, will protect its sources and continue to report without fear or favour on national security and intelligence issues when there is a clear public interest."

The search warrant named investigative reporters Dan Oakes and Sam Clark, as well as the ABC's director of News Gaven Morris.  AFP agents searched the joint for information and records from the stories, and copied it onto hard drives.

A day earlier, the AFP raided the home of of News Corp journalist Annika Smethurst, who had reported on secret plans to allow government spying.

Home Affairs minister Peter Dutton has not commented, but the opposition is clearly troubled.  Labor requested a briefing from Dutton's office to "understand why raids of such nature are warranted," according to Opposition Home Affairs spokesperson Kristina Keneally, who added:  "Freedom of the press is an essential component of our democracy."