The Eight-time world boxing champion is preparing to  retire from boxing to properly launch his bid to becoming a senator in his home country of Philiipines.

He currently represents his wife's home province of Sarangani in the House of Representatives but is always absent due to boxing duties.

Speaking during an interview, Pacquiao frowned at the concept of same sex union and describe gay couples as animals.

He gave the television interview as part of his campaign for one of 12 seats in the nationally-elected senate.

"It's common sense. Do you see animals mating with the same sex? " Pacquiao asked in an interview with TV5.

"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."

After a deluge of criticism the 37-year-old later took to his  Instagram to apologise for causing offence, but stuck to his beliefs.

"I'm sorry for hurting people by comparing homosexuals to animals. Please forgive me for those I've hurt," Paquiao said in his the Instagram video.

"I still stand on my belief that I'm against same-sex marriage because of what the Bible says, but I'm not condemning LGBT. I love you all with the love of the Lord. God Bless you all and I'm praying for you."

Gay marriage is outlawed in the Philippines due to strong opposition from the Catholic Church and 80 percent of the country's 100 million people subscribe to the faith.