Bishop Colm O'Reilly, chairman of the Catholic Bishops' National Mission Council, described turning politicians away from the altar as "extreme".
Speaking at the launch of the Irish Missionary Union's new missionary centre in Pearse Street, Dublin, Bishop O'Reilly said: "Any good priest certainly wouldn't do that to someone in public without having talked to the person in advance."
He said he would not turn away anyone without having first spoken to them in private and reminding them of the church's teachings and canon law provisions on this issue.
Bishop O'Reilly's comments follow those of Archbishop Eamon Martin of Armagh, who suggested last weekend that politicians who vote for the Government's proposed abortion legislation should not approach a priest "looking for communion".