Small Business Glossary and Definitions

Unjustifiable Dismissal is when an employee is dismissed unfairly or without reason. Employees who believe they have been dismissed unfairly may bring a lawsuit against a company. It can be difficult for an employee to prove that they have been unjustifiably dismissed, but it is important that employers understand and follow best practices for reprimanding and letting go of employees. Unjustifiable Dismissal does not include being let go for poor performance, misconduct, or redundancy.

http://www.findlaw.co.nz/articles/4296/unjustified-dismissal.aspx