Archbishop Eamon Martin, who was installed in April as coadjutor of the Armagh archdiocese, told a Radio Ulster audience that support for legal abortion is incompatible with the Catholic faith.
However, he said that he had never denied Communion to anyone and did not anticipate doing so in the future.
Archbishop Martin will become head of the Armagh archdiocese, and thus successor to St. Patrick, upon the retirement of Cardinal Sean Brady.
Cardinal Brady will mark his 75th birthday next year, but may announce his retirement before that time.