There are the well-dressed and those who missed the mark, the celebrities and average punters, those who bring a cut lunch and those who are wined and dined.

And there's no starker division than that between the winners and the losers.

Mitchell Oliver from Burnie, Tasmania, epitomised that difference.

After the day's main race was run the boilermaker from welder and his mates were half way towards landing more than $15,000 on "quaddie" bet over four races.

A win and the group were threatening to cancel their return flights. A loss and they walked away $700 lighter in the pocket.

But Mr Oliver also represented another divide. Black and white is the Derby Day fashion tradition, but the 29-year-old seemed not to get the memo.

"It's just your stock standard action back, blue overalls blending into a Hawaiian shirt and topped with a limited-edition straw hat and snake skin shoes," he said when asked to describe his outfit.

Mr Oliver was cheering on his horses from Flemington's front lawn - a stretch of grass where punters threw down picnic rugs and pulled out cut lunches.

But at the far end of the track, past the dance floors, the stables and line of security guards, the top end of town gathered in the exclusive Birdcage.

As Australia's acting Prime Minister Julie Bishop did the rounds upstairs in the Lexus marquee, food critic of MasterChef fame Matt Preston applied a spray of orange zest to a sweet described as a "modern-day fruit salad".

Inside, Fremantle star Nat Fyfe said his tips weren't paying off. But he didn't care.

"It's a great atmosphere, it's a fun day that ends up getting a bit outrageous," the Brownlow medal winner said.

Punters in the Birdcage got fashion tips from the international actors like Melissa George and bumped into the likes of Gary Ablett Jnr. in the men's toilet.

"Everyone's here, it's exciting" South Yarra luxury goods vendor and jeweller Chanel Steenkamp said.

"All the best dressed people, the marquees, Lexus, Myers ??? Everyone's well presented and well behaved."

After the final race was run and the crowd of thousands began heading home, another stark dividing line was laid bare. There were those who made a mess - and those who had to clean up after them.

When he's not doing his masters in IT, 22-year-old Aditya Kunamaneni has a casual job cleaning.

"It's just another day working for me, changing bins," he said. "It's good though, everyone seems to be enjoying themselves."

But by day's end, many of the lines of separation between different tribes had been blurred anyway - for some, literally.

Woman walked out the front gates with high heels in hand and men's shirts - carefully pressed at the start of the day - billowed untucked and creased.

And it became apparent that one new tradition had been enthusiastically taken up by all tribes at the historic event.

Young and old, well-dressed and sartorially-challenged - it seemed everyone was taking selfies.