Soros Fund Management founder George Soros. Thomson Reuters

Billionaire hedge fund manager George Soros on Thursday reiterated his belief that President-elect Donald Trump is "an imposter and con man and a would-be dictator."

Soros, 86, said at the World Economic Forum in Davos, Switzerland, that he is convinced the president-elect will fail.

"He stands for that other form of government, which is the opposite of an open society," said Soros, who is a Holocaust survivor and Hungarian immigrant. "It's really better described as a dictatorship or a mafia state."

Soros said Trump "would be a dictator if he could get away with it," but that US institutions are strong enough to prevent that scenario. He also said the ideas that guide Trump are "inherently self-contradictory" and that those contradictions are "embodied by his advisers."

Uncertainty, he said, is "at a peak" right now.

"It's impossible to predict exactly how Trump is going to act because he hasn't actually thought it through," Soros said. "He didn't expect to win. ... He was engaged in building his brand."

Asked how the business community should deal with Trump going forward, Soros said, "I will keep as far away from it as I can."

On the topic of international relations and global trade, Soros said China would be "greatly helped" by Trump.

"I think Trump will do more to make China acceptable as a leading member of the international community than the Chinese could do by themselves," he said.

This isn't the first time Soros has spoken out against Trump. He described the president-elect in similar terms in December. He said Trump's proposed Cabinet "comprises incompetent extremists and retired generals" and that the US would "be unable to protect and promote democracy in the rest of the world."

The billionaire investor supported Hillary Clinton during her presidential campaign and donated millions to a pro-Clinton PAC. He also donated to Clinton's campaign in 2008.

Soros lost about $1 billion after Trump's political victory, according to The Wall Street Journal, having made bearish bets that later came back to bite him. Still, his fund gained 5% over 2016, according to The Journal.