The head of the Church of Greece on Tuesday wore a paper mask to attend a meeting of the Holy Synod and had his temperature taken by a health worker before entering the assembly.
Photographs of Archbishop Ieronymos wearing his mask and being tested for a fever were published by the Vima Orthodoxias religious website.
The move is seen as sending a strong message to clerics and members of the congregation who continue to resist regulations imposed by the government to stem the spread of the novel coronavirus.
Under the regulations, clerics and members of the public are obliged to wear a mask during all indoor assemblies and when physical distancing cannot be observed out of doors.
A handful of priests and faithful have resisted the rules, leading to fears of localized outbreaks.