Fragments of a cassock worn by Pope John Paul II are being offered for sale to the faithful, causing concern in the Vatican over the resurgence in the veneration of relics.

Devotees of John Paul can apply via e-mail, fax or post for fragments of a white cassock to augment their prayers. A cassock worn by John Paul has reportedly been cut into 100,000 pieces to satisfy demand.

The scheme is run by the Vicariate of Rome, which is promoting sainthood for John Paul. The faithful also receive a “holy card” with a prayer to “obtain graces through the intercession of John Paul II”.

The Vicariate said that it has been overwhelmed by requests for the relics, with priority now being given to those who were praying for the sick or were themselves seriously ill.

But the scheme has caused disquiet in the Vatican, which is anxious to discourage the veneration of relics, seen as a medieval practice with no place in the modern church. “Wars were fought over the hunt for relics in the Middle Ages,” said Bishop Velasio De Paolis, secretary of the Apostolic Signature, the Vatican’s top judicial body.

Condemnation of the sale of relics – or simony – was one of the causes of the Reformation in the 16th century, together with usury and the sale of indulgences. All were later banned under Catholic canon law. “No-one can say whether venerating relics aids prayer, it depends on the faith of the believer”, Bishop De Paolis told La Stampa.

The Vicariate solicits donations from those who apply for its fragments, risking further criticism from the Vatican which forbids the sale of relics. The Vicariate claims the donations are needed to cover costs, with any surplus going towards the costs of John Paul’s “cause for sainthood”.

“This is not a commercial operation,” said Father Marco Fibbi, spokesman for the Vicariate. Fragments would be sent to those who did not make a payment as well as to those who did.

The relics on offer are known as ex indumentis, meaning cloth that the late Pope touched. The Vicariate said it had been overwhelmed by requests for the relics, and donations to the beatification website had increased to 1,200 a day from 300 a day when it was launched four months after John Paul’s death. Thousands continue to file every day past the late Pope’s tomb in the crypt of St Peter’s Basilica.

Pope Benedict XVI has put his predecessor on a fast track to beatification. At John Paul’s funeral two years ago mourners chanted Santo subito! – Sainthood now! To be beatified a candidate must be held by the Vatican to be responsible for a miraculous cure after death, a condition apparently met in the case of John Paul by a French nun who was cured of Parkinson’s disease after praying to him.

Donations to the website can be made by credit card or bank transfer. However, Monsignor Slawomir Oder, the Polish priest in charge of John Paul’s cause, warned devotees of the dangers of imitation websites offering false relics. Last year a religious souvenir shop near the Vatican withdrew supposed relics of John Paul from sale after admitting that the specks of cloth were “third-class relics” – pieces of cloth that had been laid on Pope John Paul’s tomb, rather than fragments of the Pope’s own clothing.