The Union Haddiema Maghqudin has written to Malta Public Transport requesting official recognition.
It said in a statement it already had the majority of bus drivers as members but the company had not yet carried out the necessary verification for the union to be given recognition.
More categories of workers had joined the union in recent months putting it in a stronger position to request recognition.
It warned that if discussions continued with another union and the verification process was delayed it would consider all the necessary actions to safeguard its members.
In a reply, the company reserved the right to hold the union responsible for damages it could suffer as a result of industrial action since, through its requests, the union was expecting the company to breach a court order.
It noted that a civil court decision prohibited it from proceeding with a verification process or from giving the UHM partial or full recognition.
The UHM, the company said, knew that its warrant of prohibitory injunction to stop the company from proceeding with negotiations with the General Workers’ Union, which was currently the recognised union, had not accepted by the courts.