A strike is not the only way to express opposition. 

Trade unions can undertake other lawful actions, such as:

• pickets,

A picket involves a group of people publicly expressing a position, usually at a location related to the issue at hand. It can serve to present employee demands and draw attention to their situation

• information campaigns,

An information campaign aims to convey information about a problem, dispute, or employee demands to employees or the general public.

• demonstrations,

A demonstration is a public expression of a position by a larger group of people. It can serve to present employee demands and draw attention to a specific problem.

• other actions drawing attention to the employees’ situation.

Keep in mind that not every form of protest is a strike. A strike is a specific form of action regulated by provisions on collective disputes.