Cleveland (AFP) - Leading Brexit campaigner Nigel Farage, who flew to America as a guest of the Republican National Convention, admitted Wednesday that its nominee for president, Donald Trump, makes him wince.

The man who resigned as leader of the UK Independence Party after Britain's shock vote to quit the European Union drew parallels between support for the US billionaire and last month's referendum.

At a forum hosted by McClatchy, Farage said he "understood" that the Republican nominee was trying to reach frustrated and even "scared" voters but said "just occasionally the style of it, that makes even me wince a little bit."

The British politician, known for his own populist style, described some of Trump's comments as "pretty out there" and singled out his proposed ban on Muslims entering America as "difficult to enforce."

Farage said he came to Cleveland following an invitation, and while it would be as a "big mistake" to tell Americans how to vote, he claimed he would not vote for Hillary Clinton "if you paid me."

"What Trump gets right, it seems to me, is he's prepared to talk about some of the issues that perhaps others find a bit awkward, a bit uncomfortable," he said.

He complained about Clinton's "sense of entitlement" and called Barack Obama America's "most anti-Britain" president who felt "resentment" to a country that traditionally considers itself America's closest ally.

Obama visited Britain shortly before the referendum and warned Britons they would be "at the back of the queue" of a post-Brexit trade deal.

"He was rude to us. He told us what we should do," Farage said.

Neither was he the only right-wing European politician in attendance at the Republican convention. Dutch far-right politician Geert Wilders, who also wants to leave the EU, attended on Tuesday.