Eight-division world champion boxer Manny Pacquiao has caused outrage by describing gay couples as "worse than animals".

The 37-year-old, who has won 57 of his 65 professional bouts in the ring, now focuses much of his time on politics in his homeland the Philippines.

Pacquiao is running for a senate seat ahead of the country's elections in May, and during an interview with local broadcaster TV5, the sportsman gave his thoughts on same-sex relationships.

"It's common sense," said Pacquiao. "Do you see animals mating with the same sex? 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."

In response to the boxer's remarks, singer Aiza Seguerra, who recently married her girlfriend, wrote on Instagram: "I am so fuckin mad I don't know what to say.

"You might've done our country proud but with your statement, you just showed the whole country why we shouldn't vote for you. And yes, I think you are an ignorant, bigoted hypocrite. You made me lose all respect that I had for you, Mr. Pacquiao."

Same-sex marriage is illegal in the Philippines.