Pope Francis is reported to have acknowledged the existence of a "gay lobby" inside the Vatican.
He also said there was a "stream of corruption", according to reports in Catholic media.
He is said to have made the remarks during a private meeting with a group of Latin American Catholic clerics.
The clerics wrote up a report of the conversation that then appeared on the Chilean website Reflection and Liberation.
According to the report, the Pope was extremely open as he discussed problems at the Vatican.
He is said to have told the Latin American delegation that there were good, holy men in the administration, but that there was also corruption.
The Vatican would have to "see what we can do" about the "gay lobby" operating in the bureaucracy, he said. "It is true, it is there," the report quotes him as saying.
In the days leading up to Pope Benedict XVI's resignation in February, the Italian media carried many un-sourced reports that gay Vatican clergymen had been working together to advance their personal interests, leaving the Holy See vulnerable to blackmail.
There were even suggestions that the situation had influenced Benedict's decision to resign.
At the time, the Vatican vigorously denied all the rumours.
It has so far declined to make any comment regarding the Pope's reported remarks, other than that the audience with the Latin American clerics was private.
An organisation representing the clerics, known by its Spanish acronym CLAR, has said it has apologised to the Pope for the publication of the report.
CLAR said in a statement that it "deeply regretted the publication of a text which refers to the conversation with the Holy Father".