MANILA, Philippines - Thousands of Roman Catholic priests were set to make mass confessions of their sins to each other on Wednesday.

The Catholic Bishops Conference said on its website the rare event was to be held behind closed doors in Manila during the annual congress of about 7,000 priests in the Philippines, one of few Catholic outposts in Asia.

About 5,500 priests were set to take part in the mass confession on Wednesday afternoon at a convention centre where the congress was being held.

Monsignor Pedro Quitorio, spokesman for the bishops, said that, while priests lining up before a confessional box is not a common sight, they were also humans and not without sin.

"It?s the same process. There?s also penance and absolution," he told reporters.

Quitorio said priests, including bishops, were free to approach any of their colleagues to make their confession.

"It will be face-to-face. They can choose whoever they want to confess to," he said.

About 75 million Filipinos, out of a national population of 93 million, are Catholics, a legacy of the country's Spanish colonial past.