An elderly Belgian priest who is a noted activist in the alter-globalisation World Social Forum has admitted abusing a minor family member 40 years ago, a Belgian daily reported Wednesday.

Francois Houtart, 85, told Le Soir he was the target of a complaint addressed to a Belgian Roman Catholic Church-backed commission that published in September details of hundreds of cases of child sex abuse, causing a major scandal.

The sister of a boy aged eight at the time, a cousin of Houtart, claimed the priest twice entered the boy's room while staying with Houtart to "rape" him.

Contacted in South America, the priest was quoted as saying that "while crossing the room of one of the boys in the family, I indeed touched his private parts twice, which woke him and scared him."

The priest, the object of a stalled campaign for nomination to the 2011 Nobel Peace Prize, described his action as "inconsiderate and irresponsible."

The World Social Forum, based in Brazil, was set up as a counter-point to the World Economic Forum of leaders held in the Swiss resort of Davos each year.