Conduct inconsistent with the continued confidentiality of the communication will result in a waiver of the privilege. This will arise, in particular, when the client knowingly and voluntarily discloses the substance of the evidence publicly or to another person, or the substance of the evidence is disclosed with the express or implied consent of a client. The test is concerned with the behavior of the holder of the privilege, not their intention.

Where a reference is made in a communication to the gist, conclusion or substance of legal advice, this can potentially result in a waiver in respect of the whole advice and other documents reasonably necessary to understand that advice. Particular caution should be exercised when referring to advice in correspondence with another party, or in publicly available documents such as financial reports, ASX announcements and takeover documents.

There are a number of exceptions to the doctrine of waiver, including the following:

Compulsion of law: Disclosure in accordance with a legal obligation to disclose is not a waiver. This will include situations where a regulator has the power to compel the production of privileged documents. However, a regulator will not ordinarily have the power to compel the production of privileged documents, and if in those cases otherwise-privileged documents are provided voluntarily to a regulator, then privilege is likely to be waived.

Common interest: A document may be disclosed to another without waiving privilege where the parties’ interests are aligned. Individual interests must not be selfish or potentially adverse. Companies in the same corporate group will not automatically share a common interest. It will be a question of fact in each case.

Limited purpose waiver: Where a document has been confidentially disclosed for a limited and specific purpose (for example, to conduct due diligence), then privilege will not be waived if the circumstances are not inconsistent with maintaining the privilege. The original holder of the document must retain control of the document and take steps to limit its disclosure and otherwise maintain confidentiality.

Inadvertent waiver: Where a privileged document is disclosed by mistake, it is possible to assert that there has been no waiver of privilege. However, it is important to take steps to recover the document as soon as the inadvertent waiver is discovered.