The general requirements for an individual to validly execute a deed are outlined in the relevant state based statutes. Almost all jurisdictions require that, among other things, the signature of an individual signing a deed be witnessed by an independent person.

The relevant state-based Acts, and their requirements in relation to witnessing, are outlined below:

As you can see, all states except for Victoria specifically require individuals’ signatures to be witnessed when they execute a deed. Although, the Property Law Act 1958 in Victoria does not specify a requirement that the signature of an individual signing a deed be witnessed by an independent person, in practice, signatures of individuals are witnessed in Victoria as well.

Companies are governed by the Corporations Act 2001 (Cth) (Corporations Act). As the Corporations Act is an act of the Commonwealth, electronic transactions (including electronic signatures) under it will need to be assessed under the ETA Cth.

Section 127 of the Corporations Act outlines how a company may execute a document (including a deed). In short, it states that companies may execute documents in the following manner:

A company may execute a document without using a common seal if the document is signed by:

(a) two directors of the company; or
(b) a director and a company secretary of the company; or
(c) for a proprietary company that has a sole director who is also the sole company secretary.

A company with a common seal may execute a document if the seal is fixed to the document and the fixing of the seal is witnessed by ... (refer to (a), (b) and (c) above).

If a company executes a document in a manner outlined above, third parties are able to rely on the assumption provided in Sections 129(5) or (6) (as the case may be) of the Corporations Act that the document has been duly executed by the company.

Section 127 further states that the section does not limit the ways in which a company may execute a document, including a deed. This means that, for example, a company could execute a document under the terms of its constitution using a method that may differ from the methods outlined in Section 127. However, should a company sign a document in a manner not specifically outlined in Section 127, the assumptions that the document has been duly executed by the company do not apply.

The above are also the reasons why an SMSF trust deed cannot be executed by electronic signature - i.e. third parties cannot rely upon Section 127 of the Corporations Act as the entire Act is excluded from the provisions of the Electronic Transactions Act 1999.

More detail can be found in this article here: Exploring the dangers of electronic signatures

SMSFs however can use electronic signatures for virtually all other documents relating to the ongoing management of the SMSF including trustee minutes, declarations and signing of the annual accounts and tax returns.