Champion broodmare Circles Of Gold has died aged 25 at Segenhoe Stud in the NSW Hunter Valley.

The winner of the 1995 AJC Oaks, Circles Of Gold produced her own Australian champions - Elvstroem and Haradasun - and is the granddam of multiple Group One winner Highland Reel who claimed victory at the weekend's Breeders' Cup meeting.

Peter O'Brien, general manager of Segenhoe, posted a tribute to the mare on Facebook on Wednesday.

"It is with deep sadness that I have to report that Champion Broodmare Circles Of Gold passed away peacefully and quietly today at Segenhoe," O'Brien said.

"I had the true honour to have been associated with her for 21 of her 25 years and she truly was one of a kind . A beautifully quiet mare whose exploits through her daughters and granddaughters will continue on for many years to come and it is fitting that her Grandson #HighlandReel won the Breeders' Cup World Championships on Sunday to highlight her lineage.

"She will be buried alongside her great mates and champions also #Parfore and #Skating on top of a hill at Segenhoe and I would like to thank Frank Tagg , Frank Meduri and Garry Moffit her owners who have spared no expense with her care long after she retired from breeding.

"She will be sorely missed by all at Segenhoe and everyone is acutely aware of the privilege it was to have been associated with her . RIP"