The common law defence of qualified privilege allows free communication in certain relationships without the risk of an action for defamation - where the person communicating the statement has a legal, moral or social duty to make it and the recipient has a corresponding interest in receiving it. Giving a reference for a job applicant, answering police inquiries, communications between teachers and parents, local councillors, officers of companies, employers and employees, or traders and credit agencies, are all relationships that are protected by qualified privilege. However, the privileged communication must relate to the business at hand - the relationship cannot be abused for the purpose of relaying gossip.

A defendant who is acting in defence of her or his reputation can claim qualified privilege, as long as what is said is relevant to that defence. It is also available even if what was said was untrue, as long as the required relationship exists. However, qualified privilege is not a licence to say untruths. People making statements must believe that what they say is true.

The defence of qualified privilege cannot be successful if it can be proved by the plaintiff that the defamation was motivated by malice; for discussion on malice see Fair Comment.

Government and political matters are proper subjects for public discussion and such discussion is covered by the defence of qualified privilege. To maintain the defence of qualified privilege for such publications, the publisher must have acted reasonably in the circumstances and not been motivated by malice.

Section 28 of the Defamation Act 2005 (SA) provides a broader statutory defence of qualified privilege, where the recipient of defamatory matter has an interest or apparent interest (i.e. more than just prurient or in gossip) in having information on a subject and the defamatory matter is published by the defendant in the course of giving the recipient information on that subject. The defendant's conduct in publishing the matter must also have been reasonable.

Section 28(3) sets out the following factors the court may consider in determining whether the publisher has acted reasonably:

In order for the defence to apply, the party making an otherwise defamatory statement must be subject to a duty to make the statement, and the statement must be made to a party bearing a corresponding interest in receiving the information [s 28(1)]. It is not necessary to prove that the matter published concerned an issue of public interest to establish the defence of qualified privilege [s 28(3b)].