Former New Zealand allrounder Chris Cairns is in an intensive care unit at a Sydney hospital after being moved from Canberra for urgent treatment following a serious heart incident.

St Vincent's Hospital in Sydney confirmed Cairns had been admitted on Tuesday. "He is in a serious but stable condition in intensive care," a spokesperson said.

On Wednesday Cairns' wife, Melanie, issued a statement confirming that he had undergone further surgery.

"As has now been widely reported in the media, Chris suffered a major medical event in Canberra late last week. He initially underwent surgery in Canberra, but the seriousness of his condition is such that he has now been transferred to St Vincent's hospital in Sydney, where he has undergone further cardiovascular surgery," she said.

"Chris' family and friends are heartened by the respectful and warm manner in which this terrible news has been reported, and received by the public, both in New Zealand and around the world, and thanks everyone for their warm wishes, prayers, and kind words.

"For now, no further statements will be made regarding Chris' situation, and the Cairns family asks that people continue to respect their privacy as they deal with this difficult, upsetting and concerning situation."

New Zealand media outlet Newshub on Tuesday reported 51-year-old Cairns had suffered an aortic dissection which is a tear in the body's main artery.

Regarded one of the best allrounders of his era, Cairns played 62 tests, 215 one-day internationals and two T20 matches for New Zealand between 1989-2006 before becoming a television pundit. His father Lance also represented New Zealand in cricket.

The news has rocked New Zealand, where former team-mates expressed sympathy for his family.

"It's absolutely devastating. It's the worst news you could possibly get," former New Zealand team-mate Chris Harris told local media.

David White, the chief executive of New Zealand Cricket, said: "We're deeply concerned to hear of Chris Cairns' medical emergency. Our thoughts are with his family in Australia and here in New Zealand. Chris is a much loved husband, father, and son - and remains one of our finest allrounders. We hope he's able to make a full recovery."

Cairns has lived in Canberra for several years with his children after his marriage in 2010.