The Basilica of Our Lady of the Rosary in Lourdes, France, one of the holiest pilgrimage sites for Catholics, has started covering up works by Slovenian priest and artist Marko Rupnik amid an ongoing investigation of allegations that he brutally sexually abused multiple nuns.

The mosaics on the side doors of the basilica have been covered with boards, while the ones on the main entrance will be covered shortly, before the start of the pilgrimage season, Bishop Jean-Marc Micas told the French press agency AFP on 31 March.

The work was commissioned in 2008 on the 150th anniversary of the Virgin Mary allegedly appearing to a 14-year-old girl at the site.

Rupnik, 70, a world-renowned mosaic artist, is accused of having psychologically and sexually abused at least twenty women over nearly three decades, mostly within a community he led in Ljubljana that has since been disbanded.

The mosaics in Lourdes are being covered just before the French Bishops' Conference is slated to organise a meeting in Lourdes dedicated to the fight against sexual violence, an event that many victims have been invited to.

The decision to cover the mosaics comes even though five of Rupnik's victims have urged church authorities to remove his works from Lourdes, Damascus, Washington and Vatican, saying that they are inappropriate and retraumatize the victims.

In what has been one of the biggest sexual abuse scandals in the Catholic church in years, Rupnik has been expelled from the Jesuit order but remains a priest. He is currently in Montefiolo, a monastery not far from Rome, according to Italian media reports.

The Vatican dicastery investigating the case initially found the charges against Rupnik to have been statute-barred, but after the decision prompted an outcry Pope Francis reopened the case in October last year.

It was decided that Rupnik would be tried by a Vatican court, where the selection of judges is currently underway.

Rupnik's mosaics adorn more than 200 churches and sanctuaries around the world.