The excitement of Ocean Park's Cox Plate win has been tempered by concerns over the health of his sire Thorn Park who is battling laminitis.

The 2004 Stradbroke Handicap winner was withdrawn from stallion duties at New Zealand's Windsor Park Stud last month after contracting an infection leading to the debilitating hoof disease.

Although thrilled with Ocean Park's win, Windsor Park general manager Rodney Schick said Thorn Park had suffered a setback last week.

"It's huge - a great result for New Zealand," Schick told the Waikato Times.

"Unfortunately Thorn Park has taken a bit of a step back in the middle of last week but with laminitis there's always setbacks.

"He's still in great spirits and he's fighting hard but there's a long way to go yet.

"Whatever happens, we've been very lucky to have had Thorn Park's services and a Cox Plate win is a fantastic result for him."

Ocean Park beat three-year-old All Too Hard in Saturday's Cox Plate at Moonee Valley to score his fourth successive Group One win.