A Cypriot monk caught at a Greek airport with the skeletal remains of a nun in his baggage on the weekend told authorities he was taking the relics of a saint back to his monastery.

The 56-year-old Cypriot was detained at Athens airport on Sunday after security staff discovered a skull wrapped in cloth and skeletal remains in a sheet inside his baggage.

"They maintained it was a woman who was a saint," a Greek police official who declined to be named told Reuters on Tuesday, adding that the monk told authorities he was transferring her remains to a monastery in Cyprus.

The remains were those of a nun who died four years ago. She was not a saint in the Greek or Cypriot Orthodox Churches, but had once been a nun at a Cypriot convent, police said.

Revering the skeletal remains of saints is common in the Greek Orthodox tradition. A sect within the church may have venerated the nun even though she was not an official saint.

In many churches, venerated relics are put on display for the faithful to touch or kiss and a box for collecting donations from the faithful placed nearby.

"It appears to be the work of charlatans with a financial interest that is what I suspect," Cyprus's Archbishop Chrysostomos told journalists on Tuesday when asked about the monk's tale.

The monk was freed after being charged with theft and desecrating the dead, a misdemeanor in Greece. He was also suspended from his monastic duties for three months for going away without leave, Cypriot police said.