Collective bargaining is an arrangement under which two or more competitors in an industry come together to negotiate terms and conditions (which can include price) with a supplier or a customer.
A collective boycott occurs when a group of competitors agree not to acquire goods or services from, or not to supply goods or services to, a business with whom the group is negotiating, unless the business accepts the terms and conditions offered by the group.
Both collective bargaining and collective boycotts may raise serious concerns under the prohibitions in the Trade Practices Act against cartel provisions, anti-competitive arrangements (s. 45) and agreements between competitors to limit dealings with a particular supplier or customer (s. 4D).