The Australian entrepreneur, who owns various bars, hotels and nightclubs around Sydney, said that he initially thought it was a sick joke when he was caught up in an armed robbery at one of his hotels earlier this week.
Hemmes told the Sydney Morning Herald: "I came out [of the toilet after my friend called me] and [was] confronted with one of [the robbers] as they were trying to leave. He pulled a gun to my head and told me to get out of the way.
He said that the robbers fled the scene in a black Audi and tried to get past a police vehicle but "couldn't get through because they were wedged up against the gutter".
Hemmes was later seen criticising police for not giving chase sooner, but a police insider claimed that the owner was intoxicated and "decidedly unhelpful".
The businessman said: "That's ridiculous. 'Why would I want to hamper [the investigation]? It was my place they attacked. I was frustrated that we didn't catch them. I was frustrated that they got away.''
Superintendent Tony Crandell of New South Wales police force said: ''The police involved followed all the correct protocols... To turn around and pursue those offenders [would have been] inappropriate."
Last month, Hemmes quashed rumours of a romance with interior designer Sibella Court.
He was believed to be seeing singer Natalie Imbruglia last year and was later linked to Sneaky Sound System frontwoman Connie Mitchell.
Hemmes has also denied a relationship with swimwear model Lara Bingle.