It's only fitting the rules of Derby day be broken for someone special, especially if that someone is Black Caviar.

Randwick was awash with traditional black and white for Australian Derby day on Saturday, but hundreds of racegoers broke the strict dress code to salute the champion mare by donning hints of her signature salmon pink.

Whether it was with pink ribbons tied to suits, black dotted pink ties or salmon-tinted millinery, racegoers saluted the mare with their outfits before they cheered her widely-anticipated run in the TJ Smith Stakes.

Among those happily breaking the rules was Keith Fisher, who made the interstate journey from Geelong to Randwick wearing his $600 custom-made suit made in honour of Black Caviar's win at Royal Ascot.

"I wear this suit every time Caviar runs," Mr Fisher said of his flamboyant black polka dotted and pink satin get-up.

"I'm hoping Black Caviar wins today, and I'll win the fashions for her."

Fashions on the field judge Emma Freedman said it was a rare occasion when a horse influenced racing fashion so dramatically.

"On top of the fashion part, it means that people are paying attention to racing. They are incorporating the racing side of things with the fashion side," she said.

"At the end of the day today, Black Caviar is the star.

"Her colours are iconic and in 50 years we'll still be able to recognise them."

GQ Magazine editor Nick Smith said it was a special day to break the Derby day dress rules.

"We've bent the rules a little bit to allow the salmon and the black to come through, and I think that's awesome," he told AAP.

"It's a really nice touch that both the guys and girls are saluting a horse with fashion."

Vogue editor Edwina McCann said it was a once in a lifetime opportunity for the fashion-conscious to wear colour on Derby day.

"People have been really inspired to dress up and cheer Black Caviar on," she said.

"One of our male finalists has a little nod to Caviar with his tie, and we've also seen some full-on Caviar suits.

"It's definitely an opening if you want to wear salmon - today is the day to wear it."