A letter signed by 169 abbots representing the country's 1,750 monks and nuns said there could be "dynamic expressions of opposition" during a visit by Pope John Paul II, who they described as an "arch-heretic." The Holy Synod, the church's governing body, confirmed it received the letter.
It was the first time that Greece's monastic communities have jointly drafted such a protest letter, and was an indication of the growing rifts threatening to divide the church following its decision in early March to lift objections to a papal visit.
More than 97 percent of the native-born population is baptized into the Greek Orthodox Church, the official state religion.
Rapprochement between Roman Catholics and the Orthodox is commonly viewed with hostility by the Greek clergy, who accuse the Vatican of trying to extend its influence eastward.
The government has been urged to take steps to ensure the pope's security and prevent thousands of Orthodox zealots from holding mass protests in the capital.
"The people of the church are agitated in view of the visit," columnist Alexis Papachelas wrote Friday in the daily To Vima. "The state is obligated to take up its responsibilities in a timely fashion before the country becomes an international laughing stock."
The abbots called on church leader Archbishop Christodoulos to hold an emergency meeting of the Holy Synod to review its decision, which they said "has laid waste to our souls and consciousness."
"We strongly urge you to re-examine the entire issue and ease the agony and displeasure of the faithful," they said.
Monks living in the all-male monastic peninsula of Mount Athos have already expressed their opposition to the visit. Although Mount Athos is autonomous and has no religious jurisdiction in Greece, the views of its monks carry great weight among Orthodox worldwide.