Ouch. That looks painful.

Australia's richest person Gina Rinehart fell down a flight of stairs in the Emirates Marquee during a rare appearance at today's Melbourne Cup.

The usually reclusive mining magnate, worth a cool A$6 billion - and the 51st richest person in the world, according to Forbes magazine - turned heads on Melbourne Cup Day as she went into the Australiana-themed Emirates marquee at Flemington.

She was reportedly in good spirits after the tumble.

Rinehart falls down the stairs in the Emirates marquee on Melbourne Cup Day. Photo / AAP
Rinehart falls down the stairs in the Emirates marquee on Melbourne Cup Day. Photo / AAP

The newly slimmed down Rinehart was virtually unrecognisable aside from the media scrum that gathered around her as she made her way into the Emirates-hosted marquee.

Rinehart isn't part of the usual rent-a-crowd so she certainly brought some star power to the Cup Day Birdcage area where the crème de la crème of race goers spend the day.

Dressed in a cream lace dress, a light fur wrap and signature pearl drop earrings and a mega strand, the 62-year-old businesswoman was svelte and looking the part of a chic racegoer.

She arrived flanked by a handful of relatively unrecognisable security types, although that posse did include Olympic swimmer Mack Horton, who proved just as popular as the highly regarded business woman.

Happy to be photographed and filmed as she slowly made her way around the marquee, there was a strict no-interview policy, although the power player was happy to lounge on some of the couches dotted throughout the marquee.

Gina was joined in the Emirates marquee by the like of Eddie Maguire, Qantas boss Alan Joyce, Matt Preston, Marcia Hines, Todd McKenney, Nadia Fairfax and singer Natalie Bassingthwaighte.

Meanwhile, the Mumm champagne marquee featured Melrose Place actor Grant Show, Lindy Klim, Joel Creasey and Pip Edwards.

The Lexus marquee pulled in the likes of Jessica Gomes, actor Gyton Grant and Rachel Griffiths. Meanwhile, Myer had its star attraction, Jennifer Hawkins looking exquisite in a red jumpsuit.