A picket contemplated in section 69 of the Act must be authorised by a registered trade union . The authorisation must be made in accordance with the trade union's constitution. That means that there must either be a resolution authorising the picket or a resolution permitting a trade union official to authorise a picket in terms of section 69 (1). The actual authorisation should be formal and in writing. A copy of the resolution and, if necessary, the formal authorisation ought to be served on the employer before the commencement of the picket.
The authorisation applies only to its members and its supporters.