Traditionalist Bishop Richard Williamson plans to ordain another bishop without permission from Rome.
Bishop Williamson, who was dismissed from the Society of St Pius X in 2012, told followers the ordination will happen in Brazil on March 19.
Last year, he presided at the ordination of a bishop, also in Brazil.
Bishop Williamson said the new bishops are needed to sustain “the resistance”.
Canon law stipulates that anyone involved in the ordination of a bishop without approval from the Holy See incurs automatic excommunication.