Technology billionaire Elon Musk has been forced to defend himself after he is reported to have attended a "notorious sex party."

The man behind Tesla and PayPal was attending the event at a property in Silicon Valley according to a new book by the journalist Emily Chang, entitled 'Brotopia' which looks at the gender culture in the area.

The party, which took place in June 2017, was allegedly the scene of "drug-taking and open sexual behaviour".

The location was later identified to be the home of Steve Jurvetson, a former venture capitalist at DFJ, who had previously worked alongside Musk.

But technology blogger Paul Biggar who attended the party said that he could confirm Musk's attendance but saw no evidence of "explicit sexual behaviour".

In a statement to Business Insider, a representative of Musk said the SpaceX founder had been at the party, but had been under the impression that it was a "costume party" and spent his time talking about business, before leaving at 1am.

The full statement read: "Elon was at the party for a couple hours and left around 1am after talking with several DFJ-funded entrepreneurs about technology and building companies. His impression was that it was a corporate party with a costume theme, not a 'sex party', and there was no indication that it would become one after he left. "

Biggar and Chang differ in their takes of the night, with the former saying that he had not seen "any sex or drugs".

But Chang detailed that there were "several people laid down and started stroking one another... in what became a sizeable cuddle puddle".

In November, Jurvetson left his venture capital firm after allegations of sexual harassment were made against him.