Pacquiao, who is running for a Senate seat in his home country of the Philippines, made the comment during an election video which appeared on local channel TV5’s website.
He said animals were better than gay people because they recognise the difference between males and females.
Pacquiao is considered one of the top competitors of his generation and has previously spoke of his Christian faith.
“I have a lot of dreams and visions,” he told the Guardian, “I even heard the voice of God. When I heard the voice of God, I am trembling and melting. I feel I have died. It was an amazing, amazing experience.
“I’m happy because I found the right way, salvation, born again. We are required to be born again, all of us.
“Christ said unless we are born again we cannot enter the kingdom of God. So it’s very important to me.
“Jesus Christ said: ‘I am the way and the truth and the life. No one comes to the Father except through me.’ There is no other way. The only way is through Jesus.”
He later said sorry for his comments on social media:
I’m sorry for hurting people by comparing homosexuals to animals. Please forgive me for those I’ve hurt. God Bless! pic.twitter.com/bqjRcWqp8R
His comments about gay people were criticised by gay comedian and television host Jose Marie Viceral, known as Vice Ganda.
He tweeted that those in the LGBT community are humans, not animals. He said they are not saints but that they will pray for Pacquiao.
An LGBT group in the country said the comments showed Pacquiao had a shallow understanding of issues important to the LGBT community.
Danton Remoto, chairman of the LGBT group Ladlad, said Pacquiao’s comments betray a shallow understanding of sexual orientation and gender identity.
“He is running for a national position and he should be a senator of everybody, not just over-the-hill boxers and straight people,” Mr Remoto said, adding Pacquiao and his advisers “should bone up on LGBT issues” of the 21st century.
“Otherwise, they would be left behind in the Dark Ages, when the cavemen ruled and the numbskulls roamed the earth,” Mr Remoto said.
Singer Aiza Seguerra, a former child actress in the 1980s who is now living with another actress, spoke out against Pacquiao on Instagram: “You might’ve done our country proud but with your statement, you just showed the whole country why we shouldn’t vote for you.”
“I think you are an ignorant, bigoted hypocrite,” Ms Seguerra said.
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