The Malta Union of Teachers has declared an industrial dispute with the Secretariat for Catholic Education over the working conditions of educators at 23 schools.
According to the union, these schools are alternating students' attendance leading to "extensive pressure" on educators.
The MUT said educators at church schools have to juggle between six teaching modes, which include face-to-face and online teaching, recording of lessons, live streaming and preparing multimedia resources for those at home.
Educators were also being lumped with the "mammoth task" of preparing all lessons in the various teaching modes.
"Educators were never employed to use such teaching modes and the MUT is willing to stick to the principle that educators carry out only face-to-face teaching to students who are in schools.
"The decision to adopt this unmanageable system was not taken by educators or by the MUT but was taken by respective schools, who, without any additional effort, sought the easiest solution by multiplying the workload of educators without consideration."
MUT warned it was willing to order industrial action and it was meant to meet the secretariat on Wednesday.
The union later said that after the secretariat cancelled the meeting, it was declaring a trade dispute. Again, it warned of industrial action.
MUT said in a statement that it was not against schools providing additional services such as online learning. However, this could not be done "at the expense of blatant breach of agreements in place and with schools completely disregarding their own employees".
In a separate statement, the Church authorities said they were only willing to engage in discussion with the union once it withdrew its threats.
Reacting to MUT's "aggressive stance", it said the school authorities will continue to ensure that the health and safety of educators, students and staff in all Church schools, is safeguarded in line with the guidelines issued by the health authorities.
The Church remained committed to continuing to provide an education to more than 17,000 students, despite the challenging circumstances.
"Church authorities recognise that parents or guardians have the right to protect their children and their household in the manner they deem most suitable. This includes children who require shielding, are on quarantine or cannot physically attend school for other reasons."
They said they believed in and trusted the professionalism of their educators, and acknowledged the importance of e-learning, use of digital tools and of varied modalities mentioned in the collective agreement between the Church and the MUT.