The 51-year-old former Black Caps captain collapsed in Canberra three weeks ago, having suffered a massive heart attack - resulting in aortic dissection, a tear in the inner layer of the body's main artery.
A statement on behalf of the family, released this afternoon, said during the life-saving emergency heart surgery Cairns underwent in Sydney he suffered a stroke in his spine.
"This has resulted in paralysis in his legs. As a result, he will be undertaking a significant rehabilitation process at a specialist spinal hospital in Australia."
Chris and his family remain appreciative of the immense public support as they deal with this difficult time, the statement said.
"They also appreciate the way in which their privacy has been respected."
Cairns, the son of Black Cap legend Lance Cairns, was a right-hand batsman and fast-medium bowler. He was known as one of the finest all-rounders of his generation.
He has been living and working in Canberra with his wife Melanie and their children for several years.
He has been the chief executive of SmartSportz, a company specialising in virtual sport.
Cairns had to rebuild his life after walking out of Southwark Crown Court in London in 2015 after being found not guilty of perjury and perverting the course of justice charges in relation to match-fixing allegations.
