Two of Donald Trump's old friends have reportedly made shocking claims about what really went on at the celebrity billionaire's parties in the 1990s.

Michael Gross, a reporter for the Daily Beast, claims he spoke to two of Trump's mates from his era of lavish parties that were allegedly filled with sex and illegal drugs.

Based on what they purportedly told him, Gross writes: "I'm sorry Ivanka, I really am, because your mother raised you well and I can't blame you for supporting your father.

"But here's the sad truth: Your dad's not a dog. He's a pig."

In footage from a 2008 interview, Donald Trump praises Hillary Clinton

One of the men Gross claims to have spoken to, who is now a fashion photographer, would only speak on the condition of anonymity.

The man said he'd fathered several children since his "Trump days" and didn't want his past dredged up and made public.

According to the Daily Beast, the man claimed to have attended many of Trump's parties at the Plaza Hotel around 20 years ago, when he owned it.

They had sweeping views of Central Park and Grand Army Plaza, and were typically filled with "young girls assuming they'd get somewhere".

He said the girls were as young as 15, and "over their heads, they had no idea, and they ended up in situations. There were always dramas because the men threw money and drugs at them to keep them enticed. It's based on power and dominating girls who can't push back and can be discarded. There's always someone to pick them back up. Nobody wants to call home and say 'help me'."