Interstate rivalries were put aside as Australia's leading trainers and jockeys paid tribute to legendary mare Black Caviar on the announcement of her retirement.

The champion captured the hearts of a nation and also united an industry often split between state lines.

Lee Freedman, who trained Makybe Diva to win two of her three Melbourne Cups, said she was a more than a once-in-a-lifetime horse.

"I thought it would take a lifetime to see another Makybe Diva, but with Black Caviar we will never see her like again #greatdecision," the Hall of Fame trainer said on Twitter.

Sydney's premier trainer Chris Waller said the Peter Moody-trained mare had inspired people to become racehorse owners.

"I'm shocked. I know how good she's been for racing, she's brought owners through my door," Waller said.

"What she has done for the sport has been great."

Gai Waterhouse was also taken aback by Wednesday's announcement.

She said it was a privilege that Sydney had hosted the mare's final start when she took her winning streak to 25 in the TJ Smith Stakes at Randwick on Saturday.

"They've got to retire her at some stage and for whatever reasons they've decided, it is a wonderful way for her to go out. She has gone out in a blaze of glory," Waterhouse said.

Glyn Schofield, regular rider of Hay List who has finished runner-up to Black Caviar in four Group One races, echoed the trainers' sentiments but cheekily added it might finally give a few other horses a chance to win a big race.

"It's not good for racing for her not being around but it's good for the rest of us," Schofield said.

Most Melbourne jockeys didn't have any luck against Black Caviar on the track but almost as one they have praised the champion mare's impact on racing.

Craig Williams, one of the biggest name jockeys in the country who has ridden around the world, said the mare's retirement was "disappointing for racing" but believes she had been "the best thing you could ask for for horse racing".

"In my walk of life, I walk the streets and see people that aren't involved in horse racing, they only ask about two things now - that's the Melbourne Cup and Black Caviar," Williams said.

"She's a brand, and she's done a remarkable job for Australian racing. Of course it's disappointing, but she's going to live on as turf's undefeated champion."