R-10, r. 2 - Regulation under the Act respecting the Government and Public Employees Retirement Plan
31. For the purposes of application of section 115.1 of the Act respecting the Government and Public Employees Retirement Plan (chapter R-10), an employee is deemed to be casual if he has been hired:
(1) to hold a position which normally exists owing to a shortage or temporary absence of staff or an excess of work and which is remunerated in an essentially temporary manner;
(2) to hold a position for the purpose of carrying out a specific task of a fixed duration, except where the employment or the position is of a recurring and seasonal nature; and
(3) to fill a vacant position temporarily in the absence of eligible candidates.