Federal Attorney-General Christian Porter met with his state and territory colleagues via video conference on Monday to discuss the reform, spearheaded by NSW Attorney-General Mark Speakman.

The public interest journalism defence will require a defendant to prove that the statement was on a matter of public interest and the defendant reasonably believed its publication was in the public interest.

The reforms are hoped to bring spiralling defamation payouts under control, unclog the courts of trivial cases, and encourage plaintiffs to resolve cases without resorting to litigation.

All states and territories will enact the changes as soon as possible.

"When enacted, the amendments will reset defamation law to strike a better balance between protecting individual reputations and freedom of expression, particularly regarding matters of public interest," the attorneys said in a communique after the meeting.

Key changes also include:

* A "single publication rule" in each jurisdiction's limitation laws

* A "serious harm" threshold for defamation claims, to be determined by the judicial officer before the trial

* Clarification of the "concerns notice" procedure and procedure for offers to make amends, including requiring that concerns notices must be served with sufficient time for a response to be provided before proceedings can start

* Clarification of the operation of the cap on non-economic damages.

Another stage of reform to go out for public consultation will cover the responsibilities and liability of digital platforms for defamatory content published online.

Australian Associated Press