The Vatican has approved new guidelines from Italian bishops that allow gay men to enter seminaries as long as they abstain from sex, in an unexpected adjustment to how the global Catholic Church considers possible future priests.

Although the Vatican had not explicitly barred gay men from entering the priesthood in the past, an earlier 2016 instruction had said seminaries cannot admit men who have "deep-seated homosexual tendencies".

The new guidelines, posted without fanfare on the website of the Italian bishops' conference on Thursday, say seminary directors should consider a priestly candidate's sexual preferences, but only as one aspect of their personality.

"When referring to homosexual tendencies in the formation process, it is also appropriate not to reduce the discernment to this aspect alone, but … to understand its meaning within the whole framework of the young person's personality," state the guidelines.

The Italian bishops said they approved the document in November. The text is accompanied by a note from the Vatican's clergy office, confirming the guidelines as effective for a trial period of three years.

Pope Francis, leader of the Catholic Church since 2013, has been credited with taking a more welcoming approach toward the LGBTQ community, and has allowed priests to bless same-sex couples on a case-by-case basis.

But the admittance of gay men into the priesthood has remained something of a taboo subject. Priests who are gay often express fear about discussing their sexuality.

Francis approved the 2016 Vatican instruction, which was largely an update of a previous document issued by Pope Benedict XVI in 2005.

The pope has called for careful screening of seminarian candidates, and has in the past sharply warned priests who pursue sexual relationships to leave the priesthood.

Francis also reportedly used a derogatory word about gay people when discussing homosexuality in seminaries in a closed-door meeting last year, for which the Vatican issued a rare apology on the pope's behalf. (Reuters, excluding headline)