"These people who voted for Donald Trump are the very people that are going to suffer if you don't have a universal healthcare system," the founder of Virgin Group said on CNN's "New Day." "These people are going to be the very people that are going to suffer if Donald Trump looks after the wealthy and doesn't tax the 1%."
Trump and many congressional Republican have campaigned on a promise to repeal the Affordable Care Act.
"But to abolish it, millions of people are going to suffer in the states, poor people. People will die. The misery will come back to what happened before," Branson added.
The business magnate, who was born in London, England, was also a very vocal critic of Brexit, the United Kingdom's withdrawal from the European Union, which Trump supported.
"Universal health care is something that should be a right for citizens of the world," he said. "We're campaigning in many countries that don't have universal health care to help them introduce it."
While Obamacare had problems, Branson said Trump should rely on the business community to help fix it rather than repeal it.
"So much better if Donald Trump goes in there and says, 'Okay, it wasn't a perfect system. Let's not abolish it. But let's get some business people in to make sure (it's better),'" he said.
Despite being a Hillary Clinton supporter, Branson said he and other business executives are willing to work with the real estate mogul.
"I would just beg of him and his new administration to realize that most business leaders in America want to work with him, want to help him do these things," he said. "Not to get completely entrenched in some of the things he said in the election, which I think would be very damaging for this country and the world."