The ABC's Sydney headquarters and the Canberra home of a News Corp reporter were raided on consecutive days last year by officers searching for classified documents used to break stories.

"We may have been able to improve some of our communications and expectations of what's to occur," Mr Kershaw told ABC radio on Wednesday.

"I always think that's an area we can improve in and I have acknowledged that perhaps some of our communication could have been better in those matters."

The ABC on Monday failed in its bid to block the AFP from using seized documents relating to a story about potential war crimes in Afghanistan.

Mr Kershaw denied it was a pleasing outcome.

"We know that often the matters can be appealed so it's not over until it's over," he said.

The AFP commissioner is open to a proposal which would require law enforcement to seek the attorney-general's advice before launching an investigation into a journalist.

"That's something that I've accepted in principle. That on the surface looks pretty good. It's the 'how to' bit that's probably the more difficult component," Mr Kershaw said.

Greens senator Sarah Hanson-Young plans to introduce legislation that would force police to apply to a judge to search a media outlet or access journalists' metadata.

It would also protect whistleblowers by allowing them to use a public interest defence and protect journalists from revealing sources.

"The truth is, those in power don't want the public to know what they're up to and are shutting down transparency and accountability to serve their own interests," Senator Hanson-Young said.

"What's really at stake here is one of the pillars of our democracy. From the Afghan files to sports rorts, the Morrison government is more worried about covering its backside than national security."

Australian Associated Press