Unbeaten Australian star Black Caviar has been retired after recording the 25th victory of her career in Sydney last weekend.

Trainer Peter Moody has announced that the seven-year-old bows out with a record of 25 wins in as many starts, including 15 victories at the highest level.

Black Caviar claimed her final victory in the TJ Smith Stakes at Randwick last Saturday.

Moody told news.com.au: "(The)Owners and myself had a long chat over the last couple of days and at lunchtime today we decided 25 was a great number to go out on."

Black Caviar grabbed plenty of headlines last summer when she made the trip to Britain to contest the Diamond Jubilee Stakes at Royal Ascot.

She arrived unbeaten in 21 starts but was made to work hard for victory in the six-furlong contest, eventually holding Moonlight Cloud by just a head.

Black Caviar was subsequently reported to have suffered muscle damage during the race and did not return to action until February this year, when she won the Lightning Stakes at Flemington which was named in her honour.

Moody admitted a second trip to the Royal meeting had been in the thoughts of connections for this year, but they have decided the mare has done enough.

"Collectively the mare is in great shape. We thought long and hard about Ascot, Brisbane and Adelaide but it's a good time to finish as she's done everything we've asked of her," said Moody.

"It's time to pull the career on one of our finest horses ever.

"She's got a few aches and pains but we always wanted to make sure she finished on a good note.

"After Ascot we were going to retire but in the finish we got three more runs out of her."