Most 'Class actions' are governed in Ontario by the Class Proceedings Act, 1992 (CPA, 1992)[see below], and federally by the Federal Courts Rules under the Federal Court Act [s.334.1-334.39, see below]. In essence they are a means of 'access to justice' by large groups of people (typically consumers) who would not - individually - be financially able to advance litigation against one or several related defendants (typically corporate) due to an imbalance of bargaining power.
In some cases the Rules of Civil Procedure [RCP 12.07-12.08] also allow for class representation separate from the CPA, 1992 (see Rules of Civil Procedure, below).