See all the fashion pictures from day three of the May races here

The Adelaide woman scooped the prize for lady of the day, dressed in a stunning custom made dress by Geelong designer Lainie Brookman.

She complemented her outfit with a leather and net hat by milliner Katherine Warner.

"I was scrolling on Pinterest and I found this beautiful dress. It was woven material, but strapless," she said after her win trackside.

"I really liked the drop waist and the flare. I had this fabric lying around and I said to (designer) Lainie 'I think this would look great in a winter style'. It only arrived on Friday."

Mrs Siviour said she was a regular fashions on the field competitor.

"We love the carnival, we usually come for a week. It's amazing," she said.

Her friend Isabelle Chaplin was the runner-up lady of the day.

Beachport's Helen Varcoe took out the contemporary lady of the day prize, wearing a re-imagined vintage suit.

The intricately detailed outfit was purchased from Dulcie's Bus, a vintage clothing store in Adelaide.

"I hand-beaded the fur hat myself," she said.

"When I was announced as the winner I was going to cry. I was overwhelmed. We had a horse that was meant to run in the cup but it was injured. We still decided to come and now I have won."

The runner-up was Christina Croxford from Creswick, who made her own dress from Maticevski material.

The traditional lady of the day prize was awarded to Tara Mathuranayagam.

Ms Mathuranayagam said her eye-catching blue and grey ensemble was custom-made by Geelong designer Janet Kay.

"I was inspired by a 1950s modern vintage style," she said.

"The button design elongates and shows off a women's figure. I have matching gloves with the same buttons. This is my first winter fashions on the field competition. I have only been competing for 18 months."

The gentleman of the day award sash was awarded to Adelaide's Greg Trembath.

Dressed in a grey tweed jacket and soft pink trousers, he made a few last minute changes to his original plans.

"We have horses in South Australia and Warrnambool's carnival was on the bucket list," he said.

"My suit came together just this morning. I had a different outfit planned on Wednesday night."