VATICAN CITY (AFP) - Pope Francis has admitted the existence of a "gay lobby" inside the Vatican's secretive administration, the Curia, according to sources cited on Tuesday by religious media.

"In the Curia, there are truly some saints, but there is also a current of corruption," the 76-year-old is quoted as having said during an audience last Thursday with CLAR (the Latin American and Caribbean Confederation of Religious Men and Women).

"There is talk of a 'gay lobby' and it's true, it exists," he said.

The Argentine pope has made reforming the Roman Curia - the heavily criticised and intrigue-filled administration of the Catholic Church - a keystone of his papacy, but said it would be "difficult".

"I cannot carry out the reforms myself," he said, explaining that he was "disorganised".

For that reason, the task will be handled by a commission of eight cardinals from around the world whom Francis appointed in April to help him govern the Catholic Church, set to meet for the first time in October.