Rodrigo Duterte, president-elect of the Philippines, is going head-to-head with the Roman Catholic Church in a series of public and controversial confrontations.

Just one day after he referred to the Catholic bishops as "sons of whores", he has pledged to defy the Church and impose a three-child policy in an attempt to control the fast-growing population of the intensely-religious nation where eight in ten of the 100 million population are Catholic.

Although Duterte has not yet officially been declared winner of this month's election,  three of his four rivals have already conceded defeat after an unoffical count showed him to be in the lead. He is expected to take office at the end of next month.

Speaking in Davao City yesterday, he said: "I only want three children for every family. I'm a Christian, but I'm a realist so we have to do something with our overpopulation. I will defy the opinion or the belief of the Church."

Earlier, on Saturday, he condemned the Church as the "most hypocritical institution" and accused some bishops of enriching themselves at the expense of the poor.

"You sons of whores, aren't you ashamed? You ask so many favors, even from me," the president-elect said in an interview with GMA TV.

Monsignor Oliver Mendoza, of the Archdiocese of Lingayen, said the Church will continue to speak out. 

"Because if we fail to do that, if we close our eyes, if we close our lips, we close our ears, what will be the role of the Church?"

Last December, Duterte made a speech full of obscenities in which he cursed the Pope.

Duterte was baptised a Catholic but takes spiritual advice from Apollo Quiboloy, head of the Kingdom of Jesus Christ, an evangelical church which describes itself as a "kingdom nation".