President Rodrigo Duterte (pictured below) has previously spoken out about his view on killing those convicted of crime.
He said: "If you destroy my country, I will kill you. If you destroy our children, I will kill you."
ABC News reported that two weeks after his inauguration that around 200 drug dealers and users were killed in shoot-outs.
The bishops have issued a special letter after what they're calling a "disturbing rise" of people being removed by vigilantes.
The Catholic Bishops' Conference (CBCP) said: "We are disturbed by an increasing number of reports that suspected drug-peddlers, pushers and others about whom reports of criminal activity have been received, have been shot, supposedly because they resist arrest."
"It is the moral duty of every Catholic, every Christian, in fact, to report all forms of vigilantism of which they have personal knowledge.
"For greater reason is it a duty to keep away from any participation and any form of cooperation with vigilantes and vigilante movements."
The group also argues that "one can 'shoot to kill' solely on the ground of legitimate self-defense or the defense of others."
But the letter says that to "kill a suspect outright, no matter how much surveillance work may have antecedently been done on the suspect, is not morally justified.
"Suspicion is never the moral equivalent of certainty, and punishment may be inflicted only on the ground of certainty."
The bishop's also stress that it is not okay to receive payment to kill another human being and that if a suspect is trying to escape then authorities must use non-lethal means to try and detain them.
