The Catholic Church in the Philippines has defended Christian boxer Manny Pacquiao following his comment that gay couples are "worse than animals".

Father Jerome Secillano, executive secretary of the Catholic Bishops Conference of the Philippines, told radio station DZMM that it was "unfair" for Pacquiao to be judged on quoting from the Bible in response to a question on same-sex marriage.

"This is really in the Bible. There is this quote he (Pacquiao) uses from the Bible and we cannot change that," Secillano said.

Pacquiao, a former world champion boxer, is a member of the Philippines house of representatives. He is a popular politician in the country, where conservative views on sexuality are common, in part due to it being a Catholic nation.

He was dropped by sponsor Nike for his "abhorrent" comments that "Animals are better because they can distinguish male from female. If men mate with men and women mate with women they are worse than animals."

Though initially apologising for his remarks, Pacquiao courted fresh controversy last week when he posted then deleted a Bible verse on his Instagram account saying men who have sex with other men should be "put to death".

ABS CBN reported that in his latest social media outing on the subject, Pacquiao quoted Leviticus 20:13: "Do not have sexual relations with a man as one does with a woman; that is detestable... If a man has sexual relations with a man as one does with a woman, both of them have done what is detestable. They are to be put to death; their blood will be on their own heads."

On Friday, Pacquiao told reporters: "What I am saying is right. I mean I am just stating the truth, what the Bible says."

He added: "I'm happy. I'm always happy because God is with me."

Secillano did say on Sunday that the former boxer should not have used such offensive language when discussing his beliefs.

"The church... says that if this is your lifestyle, if this is your orientation, then we respect that, we cannot condemn them," Secillano said.