Strikes, Lockouts, Picketing and Replacement Workers

When collective bargaining reaches an impasse, and certain other legal rules are complied with, a legal work stoppage may occur. Work stoppages are typically referred to as either strikes or lockouts, both of which are often accompanied by picketing. The result is the partial or total withdrawal of labour and the near-total ban on the use of replacement workers.

A work stoppage may be initiated by the union, in the form of a strike, or by the employer, in the form of a lockout. A strike need not be a complete stoppage of work and may include labour withdrawals in the form of overtime bans, work slowdowns or rotating strikes.

The purpose of a strike is to compel an employer to agree to terms and conditions of employment, whereas a lockout is intended to exert similar pressure on the employees and the union. The practical result of each, in terms of the impact on the employer’s business, is virtually identical.


The Labour Relations Code prohibits employees bound by a collective agreement from striking during the term of that agreement, and the union must not declare or authorize a strike of those employees during that term. Similarly, an employer bound by a collective agreement must not during the term of the collective agreement lock out employees bound by the collective agreement.

Where the collective agreement has expired, a legal strike or lockout still cannot occur until the following preconditions are all met:

  • The union and employer must first have engaged in good faith collective bargaining.
  • A vote must have been held to determine if the majority of employees favour a strike, or, in the case of an accredited employers’ organization, if the majority of the employers in the organization favour a lockout.
  • Strike or lockout notice of 72 hours must have been given to both the other party and to the Labour Relations Board.
  • If a mediation officer has been appointed by the board or by the Minister of Labour and Citizens’ Services, that appointment must have come to an end, and 48 hours must have passed.

A strike or lockout that does not meet these preconditions constitutes a breach of the Code. Similarly, a strike that takes place during the term of a collective agreement is a breach of that agreement’s mandatory no strike/lockout clause. A variety of remedies are available in the event of an illegal strike or lockout. These remedies include cease-and-desist orders issued by the board or compensation for damages through the grievance arbitration process in the collective agreement.


When a legal strike or lockout is in progress, the Code allows employees to picket. The purpose of picketing is to exert pressure on the employer by persuading other people not to do work for, or do business with, the employer. However, a picket line must be peaceful and cannot be used to forcibly prevent people from entering an employer’s premises. Note also that in 2019, the Code definition of picketing was amended to specifically exclude lawful consumer leafleting from being considered picketing so long as, effectively, it does not interfere with access to a business or prevent employees from getting to and from work.

Usually, striking or locked-out employees are only entitled to picket where they normally perform the work that’s an integral and substantial part of the employer’s operation and which is under the control and direction of the employer. Other operations of the employer may not normally be picketed. For example, if you operate your business at more than one location, your striking or locked-out employees are only permitted to picket the location for which their union is certified and at which they perform their work for you. They are prohibited from picketing your other locations if they do not normally perform work at those locations.

As an exception to this general rule, picketing may also be conducted at other sites, with permission from the board, in circumstances where an employer attempts to have “struck work” performed at these other sites. In other words, if you move work, normally performed by striking or locked-out employees, to another location in order to continue service or production during the strike/lockout, that location may be subject to picketing.

Similarly, striking or locked-out employees may be entitled to picket the place of business of an “ally” employer. The board will declare another employer to be an ally of the struck employer in circumstances where the ally assists the employer in a lockout or in resisting a lawful strike. Ally picketing is restricted to the site at which the ally performs work for the benefit of the employer who is directly involved.

Finally, where more than one employer carries on business at the same site (referred to as a “common site”), the board generally restricts picketing so that it affects only the employer involved in the labour dispute or the ally of that employer. This restriction is relaxed, so that regulated picketing at a common site can occur and will affect third parties to some degree, in circumstances where the union has no other way of picketing at the workplace of the striking or locked-out employees.


Employers are extremely limited as to the hiring of replacement workers during a strike or lockout. In broad terms, the code provides that the only people who may perform the work of the striking bargaining-unit employees are management people who work at the same location and non-bargaining unit employees who also work at the same location and consent to performing such work. In either situation, the replacement employee must have worked at that location prior to the date that notice to bargain was delivered.

The board provides a series of online resources covering strikes, lockouts, picketing and the use of replacement workers in much greater detail. You are encouraged to examine these resources carefully by visiting the following sites:

Information provided by Ryan Anderson, an employment lawyer with Mathews Dinsdale & Clark LLP. The information provided in this article is necessarily of a general nature and must not be regarded as legal advice. For more information about Mathews Dinsdale & Clark LLP, please visit