The BCEA and the Labour Relations Act aim to promote collective bargaining, and therefore allow variation of certain specified conditions through collective bargaining between an employer and employees who work for that employer. They can reach a collective agreement.

A collective agreement under the BCEA may have different conditions to those in the BCEA, as long as they are more favourable to the employee than the BCEA. If an agreement breaks any part of the BCEA, it is not enforceable and the BCEA conditions override the conditions in the agreement.

There are also centralised agreements (Bargaining Council Agreements) under the Labour Relations Act. In centralised collective bargaining , employees may agree to conditions that are different to BCEA conditions. This may be because in exchange they gained something else they wanted more.(See: Collective Agreements)