(1) If neither the contract of employment of the employee concerned nor any employment regulation order, registered employment agreement or collective agreement that has effect in relation to the employee specifies the normal or regular starting and finishing times of work of an employee, the employee's employer shall notify the employee, subject to subsection (3), at least 24 hours before the first day or, as the case may be, the day, in each week that he or she proposes to require the employee to work, of the times at which the employee will normally be required to start and finish work on each day, or, as the case may be, the day or days concerned, of that week, and the employee's employer shall, other than where the employee is a person holding office under, or in the service of, the State as a member of the Defence Forces, ensure the work takes place within predetermined reference hours and days.