Dear Dipaknsk,
Welcome to CiteHR. To get better and complete solutions to your queries, you must furnish all relevant information about your organization, the applicable laws/Acts, location, size, type of business activity, etc.
Whether it is a union leader or an employee, I trust that you must have a provision/list of "misconducts" in your Standing Order, Conduct & Discipline rules, Code of Ethics, etc., to deal with the situation.
Warm regards.