Billionaire Tom Perkins has apologised after he sparked outrage by saying that rich Americans are being persecuted like 'Jews in Nazi Germany'.

The venture capitalist apologised for using the word 'Kristallnacht' in a letter where he drew parallels between America's "progressive war" on the rich and the persecution of Jews by the Nazi regime.

But the co-founder of Kleiner Perkins Caulfield & Byers stood by the message of his controversial letter, where he likened the Occupy movement to Kristalnacht.

Speaking to Bloomberg TV, he said: "It was a terrible word to have chosen."

But Perkins was unrepentant about the broader comparison, claiming that the richest one per cent of Americans are being "demonised" just like Jews were under Nazism.

"The letter said what I believe: I believe we have to be careful that we don't demonise anybody and we don't demonise the most creative part of society," he said. "As a class, we are beginning to engage in class warfare. The rich as a class are threatened through higher taxes, more regulation."

In his letter to The Wall Street Journal titled "Progressive Kristallnacht Coming?", Perkins said: "I would call attention to the parallels of fascist Nazi Germany to its war on its one percent, namely its Jews, to the progressive war on the American one percent, namely the rich.

"From the Occupy movement to the demonisation of the rich embedded in virtually every word of our local newspaper, the San Francisco Chronicle, I perceive a rising tide of hatred of the successful one per cent."

Kristallnacht, also known as the Night of Broken Glass, refers to a series of coordinated raids against Jews throughout Nazi Germany in November 1938.

During the interview, Perkins, who was educated at MIT and Harvard university, also took a moment to boast about his Richard Mille luxury watch.

He said: "This isn't a Rolex. I could buy a six pack of Rolexes for this".

Perkins was recently in the news after spending $150 million building a super yacht called the Maltese Falcon.