Pentire, the sire of Melbourne Cup winner Prince Of Penzance, has died at Rich Hill Stud in New Zealand.

The 25-year-old stallion was taken ill on Monday, and died after surgery for an intestinal tumour.

"He was 25, but I thought he was going to live forever. He was still serving and so healthy and well," Rich Hill studmaster John Thompson told NZ Racing Desk.

"We noticed after lunch on Monday he looked a bit uncomfortable and I got a bad feeling about it. In 20 years we'd only had the vet to him twice.

"We got him to the clinic and he went into surgery and when they opened him up they found a tumour that the intestine had wrapped around.

"They removed the growth and the intestine hadn't been compromised. They got him into recovery, but sadly he didn't wake up."

Pentire was a dual Group One winner of the Irish Champion Stakes (2000m) and the King George VI & Queen Elizabeth Diamond Stakes (2400m) before his retirement in 1997.

He has left 16 individual Group One winners, nine of them in Australia including 2015 Melbourne Cup winner Prince Of Penzance while (King) Mufhasa won at the highest level on both sides of the Tasman.

Pentire's Group One roll of honour also features Xtravagant, now at stud in NSW, Zarita, Rangirangdoo, Pantani, Art Success, Penny Gem, Pentane, Recurring, Markus Maximus, Say No More, Chenille, Volatile Mix and Ferlax.

Pentire shuttled between Japan and New Zealand in the early years and also spent two seasons in Germany before he was permanently domiciled at Rich Hill in 2005.

"It just won't be the same around here without him, but his legacy will live on and Pentire is always going to be seen as a strength in any pedigree," Thompson said.

"He's had four Group One winners in the last two seasons and I'm certain there are more to come."

Pentire was buried at Rich Hill on Tuesday.