"You sit there with your girl and she starts talking about family stuff and then all of a sudden she says a name that you know and all of a sudden it's like: 'Oh s***, we might be related'." His comments about Polynesian couples being "taboo" have been of particular concern - with people from around the world blasting Shelton on social media sites.
"Just the thought of people dating the same culture, Polynesians dating other Polynesians. You never see it nowadays. It's always been kind of like ... a taboo type of thing. You don't see people dating the same race," he said.
A second video was posted 24 hours later of Shelton apologising to fans.
New Zealand-based Polynesian women's magazine, SUGA, had more than 200,000 views on its Facebook page after it posted a link on its website, which was viewed 50,000 times. Editor Cecilia Sagote said the majority of feedback was of disappointment and anger.