There are many circumstances in workplace and fair work law where it is necessary to decide whether a “workplace instrument” applies to an employee’s employment. It is an important issue in the general protections of the Fair Work Act, but in many other contexts as well. Is a written employment contract a “workplace instrument”? The answer is no for the purposes of the general protections but yes in many other contexts; see sec 341(1), Fair Work Act 2009.
“The word “instrument” is not defined in the Act. Neither is it defined in s 46 of the Acts Interpretation Act 1901 (Cth). In Azevedo v Secretary, Department of Primary Industries and Energy (1992) 35 FCR 284 at 299–300 French J relied on the “ordinary English meaning” of the word, that being “a formal legal document whereby a right is created or confirmed, or a fact recorded; a formal writing of any kind, as an agreement, deed, charter or record, drawn up and executed in technical form” (relying on the Shorter Oxford English definition).”
And see Harpham v Communications, Electrical, Electronic, Energy, Information, Postal, Plumbing and Allied Services Union of Australia  FCA 1473 per Tracey J and see also Barnett v Territory Insurance Office  FCA 968 delivered 24 August 2011 per Mansfield J
‘In the sense of recognition by acknowledging the existence of, and treating as valid, the terms of a contract of employment, subject to the operation of the FW Act, it may fairly be said that the FW Act recognises the contract of employment. …….. However, in my judgment, the concept of recognition in the definition of “workplace instrument” does not have that expanded meaning. I do not think that such a meaning can properly be derived from the context and background to that expression, or having regard to other considerations to which I refer below.
The first reason for that conclusion is that, underpinning every employment relationship is a common law contract of employment that is a contract under which a person agrees to work for another person in return for remuneration. The existence, for example, of an award does not create the relationship of employer and employee. That arises from the agreement between the employer to engage, and the employee to be engaged in employment.
The contract of employment may, subject to the law, specify the detailed terms and conditions of that employment relationship. If relevant statutory provisions or instruments such as an award or enterprise agreement sourced from a workplace law or the NES, are superimposed over that contract of employment, the agreed terms of the contract are either suppressed or unlawful to that extent. But the contract of employment itself stands. The legislative structures are built upon the premise of an agreement to employ and to be employed …