Group One-winning mare Secret Agenda is to head to the broodmare barn with connections announcing her retirement from racing.

The Mick Price-trained Secret Agenda retires having won seven of her 23 starts and earned more than A$1.5 million.

The five-year-old's biggest win came in last year's Gr. 1 Robert Sangster Stakes for fillies and mares at Morphettville, and she finished second to Shoals in her defence of the race earlier this month.

Secret Agenda's final start was in the Gr. 1 Goodwood on May 19, in which she was unplaced.

"Secret Agenda was incredibly honest, she tried her best every time despite niggling issues and a penchant for soft tracks which we don't get too often," Price said on his website.

"Although she may have had more racing in her, I wanted to retire her when she was sound and happy, she didn't owe us anything."