Deacons are ordained clerics who sit just behind priests in the Church hierarchy. They can preach and officiate at baptisms, funerals and weddings, but are not allowed to celebrate Mass, hear confessions or anoint the sick.

Attending an international meeting of nuns at the Vatican, the pope was asked why women could not serve as deacons, with one delegate suggesting it would be a good idea to create a commission to study the issue.

"I think so. It would be good for the church to clarify this point. I agree," he was quoted as saying by Italian news agency ANSA. A Vatican spokesman said he could neither confirm nor deny the comments.

The Church teaches that women cannot become priests because Jesus willingly chose only men as his apostles. However, St. Paul refers in the bible to a deaconess called Phoebe, leading liberal Catholics to argue that there is clear precedent for women to play a much more important role in Church life.

Conservative Catholics would likely put up fierce resistance to any such a move, eager to preserve clear and separate roles for men and women within the Church.

Pope Francis has stirred concern amongst traditionally minded Catholics over what they perceive as his liberal leanings on a range of issues, from divorce to the use of contraception.

Earlier this year he overturned centuries of tradition that banned women from a foot-washing service during Lent, upsetting conservatives and delighting women's rights activists.

Speaking to the nuns, the Argentinian pontiff said he had once discussed the role of female deacons in the early Church with a professor but remained uncertain about the question. "It was a bit obscure," he said.