Following the introduction of the 90 Day Trial Period provisions under the Employment Relations Act, a number of Employment Relations Authority and Employment Court cases have determined that a Trial Period is only enforceable if the Employment Agreement has actually been signed by the employee prior to or on the day they commence employment.
Generally, when an Employment Agreement has been provided to a prospective employee but has not yet been signed by the employee when they actually commence employment; the terms and conditions contained in the Agreement are deemed to be the terms under which the employee is employed. However, in such circumstances, whilst all other conditions of the Agreement would apply, any 90 Day Trial Period provisions within the Agreement would not be enforceable.
90 Day Trial Periods are only applicable for new employees, and the Authority and Court have made it clear that should an employee commence and then some time later sign their Agreement (even 1 day later), then at the time of signing they would not be a new employee as they have already been employed for a period of time and consequently any Trial Period clause would not apply.
Therefore if you wish to include a 90 Day Trial Period clause in an Agreement, it is imperative that the employee signs the Agreement either before or on the day of commencement for it to have any affect.
Obviously as an Employment Agreement is a legally binding document, it would be expected that employers should ensure all prospective employees sign their Agreement, irrespective whether it contains a 90 Day Trial Period clause or not, before employment commences.