This is what the Fair Work Commission offers up in its unfair dismissal benchbook as a very brief summary of what constitutes an unfair dismissal, assuming of course that the employee is protected from unfair dismissal, which is not the case for many Australian employees.

“Introduction
See Fair Work Act 2009 s.385(b)
Only after determining that an employee is protected from unfair dismissal, and that the employee has been dismissed, can the Fair Work Commission determine whether the dismissal was unfair within the meaning of the Fair Work Act.
In doing so the Commission must consider whether the dismissal was harsh, unjust or unreasonable. This is also called determining the merits of the unfair dismissal claim.
There are 3 substantive elements of an unfair dismissal (apart from the fact of the dismissal itself) that the Commission must be satisfied of:
1. the dismissal must be harsh, unjust or unreasonable
2. the dismissal must not be consistent with the Small Business Fair Dismissal Code (where the Code applies), and
3. the dismissal must not be a case of genuine redundancy.[1]
The power to grant a remedy cannot be exercised without the Commission being satisfied about these 3 matters.[2]
What is harsh, unjust or unreasonable?
See Fair Work Act s.387
It may be that the dismissal is:
• harsh but not unjust or unreasonable
• unjust but not harsh or unreasonable, or
• unreasonable but not harsh or unjust.[3]
The concepts of harsh, unjust or unreasonable may overlap.[4]
A dismissal may be:
• unjust because the employee was not guilty of the alleged misconduct
• unreasonable because the evidence or material before the employer did not support the conclusion
• harsh on the employee due to the economic and personal consequences resulting from being dismissed, or
• harsh because the outcome is disproportionate to the gravity of the misconduct (the punishment does not fit the crime).[5]
Criteria for considering harshness etc
In considering whether a dismissal was harsh, unjust or unreasonable, the Commission must take into account:
• whether there was a valid reason for the dismissal related to the person’s capacity or conduct (including its effect on the safety and welfare of other employees)
• whether the person was notified of that reason
• whether the person was given an opportunity to respond to any reason related to the capacity or conduct of the person
• any unreasonable refusal by the employer to allow the person to have a support person present to assist at any discussions relating to dismissal
• if the dismissal related to unsatisfactory performance by the person—whether the person had been warned about that unsatisfactory performance before the dismissal
• the degree to which the size of the employer’s enterprise would be likely to impact on the procedures followed in effecting the dismissal
• the degree to which the absence of dedicated human resource management specialists or expertise in the enterprise would be likely to impact on the procedures followed in effecting the dismissal, and
• any other matters that the Commission considers relevant.[6]”