Every worker has the right to join a trade union and this is guaranteed by Section 71 of the Industrial Relations Act 1972:
71. Every worker as between himself, his employer and co workers shall have the following rights, that is to say:
(a) the right to be a member of any trade union or any number of trade unions of his choice;
(b) the right not to be a member of any trade union or other organisation of workers or to refuse to be a member of any particular trade union or other organisation of workers;
(c) where he is a member of a trade union, the right, subject to this Act, to take part in the activities of the trade union (including any activities as, or with a view to becoming an official of the trade union) and (if appointed or elected) to hold office as such an official.
The penalties on an employer for discriminating or victimising a worker for trade union membership or activities iscovered by Section 42 of the Industrial Relations Act:
42. (1) An employer shall not dismiss a worker, or adversely affect his employment, or alter his position to his prejudice, by reason only of the circumstances that the worker—
(a) is an officer, delegate or member of a trade union;
(b) is entitled to the benefit of an order or award under this Act;
(c) has appeared as a witness or has given any evidence in a proceeding under this Act; or
(d) has absented himself from work without leave after he has made an application for leave for the purpose of carrying out his duties as an officer or delegate of a trade union and the leave has been unreasonably refused or withheld.
(2) An employer shall not—
(a) make the employment of a worker subject to the condition that he shall not join a union or shall relinquish trade union membership;
(b) dismiss or otherwise prejudice a worker by reason of union membership or because of participation in union activities outside working hours;
(c) with intent to dissuade or prevent the worker from becoming such officer, delegate or member or from so appearing or giving evidence, threaten to dismiss a worker, or to affect adversely his employment, or to alter his position to his prejudice by reason of the circumstance that the worker is, or proposes to become, an officer, delegate or member of a trade union or that the worker proposes to appear as a witness or to give evidence in any proceeding under this Act.
(3) An employer who contravenes subsection (1) or (2) is liable on summary conviction to a fine of ten thousand dollars and to imprisonment for one year; and the Magistrate making the order for conviction may also order that the worker be reimbursed any wages lost by him and direct that, notwithstanding any rule of law to the contrary, the worker be reinstated in his former position or in a similar position.
(4) In any proceedings for an offence under subsection (3), if all the facts and circumstances constituting the offence other than any specific intent, are proved, the defendant may be convicted unless he proves that he did not have the specific intent in question.
(5) Subject to subsection (3), nothing in this section shall be construed so as to compel any employer, in the absence of agreement to the contrary, to pay or compensate any worker for any time not spent in performance of the duties of his employment.