It has been held that the failure to comply with an unreasonable direction does not provide a valid reason for the termination of a person’s employment. In Izdes v L.G. Bennett & Co Pty Ltd t/as Alba Industries  IRCA 499 (14 September 1995). Beazley J stated:
“In determining whether a refusal to carry out the lawful and reasonable directions of an employer constitutes a valid reason for termination, it is necessary to have regard to all the circumstances, including the nature and degree of the employee’s conduct.” [Cf: Tranter v Council of the Shire of Wentworth (unreported, 24 October 1995, Marshall J)] See also Schreier v Austal Ships Pty Ltd, Print N9636.
Conversely the failure to follow a lawful instruction which was reasonable in the circumstances may provide an employer with a valid reason to terminate an employee’s employment: Cox v South Australian Meat Corporation.  IRCA 287 (13 June 1995) per von Doussa J.
See Felton v BHP Billiton Pty Ltd (2015) FWC 1838 1838 delivered 30 April 2015 per Hampton C