An ongoing hoof problem has resulted in the retirement of star New Zealand mare Prowess.

The Roger James and Robert Wellwood-trained mare retires as the winner of eight of her 12 races, including two at Group 1 level.

A daughter of Proisir, Prowess developed laminitis while spelling after a delayed three-run spring campaign that saw the mare win the Group 2 Crystal Mile (1600m) at Moonee Valley on Cox Plate Day.

"She developed laminitis from being out in the pasture," Wellwood said.

"She was a little bit shuffly in her action, consistent with mild foot bruising, so we changed her management and got her back into work but there was still a little bit of heat in the foot, so she went out to the water treadmill and spa.

"There was still heat in that left foot, so they took some radiographs of that foot and it showed there had been a shift in the pedal bone, consistent with some laminitis over the last few weeks.

"It's absolutely gutting that we won't see her on the racetrack again, but hopefully we can look forward to a long and fruitful broodmare career for her."

James, who had 15 Group 1 wins before teaming with Wellwood for another five at the highest level, commented that Prowess had the potential to be one of the best horses he had trained.

However, her retirement will result in the best not being seen from the mare.

"She showed tremendous ability winning two Group 1's at three, including a weight-for-age Group 1," Wellwood said.

"But what we saw of her at four winning the Crystal Mile and then running in the Champions Stakes (at Flemington), and then with another year on her, she was going to be competitive in those really high-class races.

"We're not going to see that, so we're going to have to remember that, and hopefully she can have a good life as a broodmare."