"We would appreciate it if the family's privacy can be respected during these early stages. We will be in a better position to comment publicly once we have more details from the specialists and a better understanding of the right course of action."
A broadcaster since 1970, Leishman has been a longtime fixture of New Zealand's television landscape.
Most recently he has hosted the Golf Show, but has also covered Olympic and Commonwealth Games for TVNZ, as well as yachting, tennis, league and rugby.
He was also the host of Wheel of Fortune, the country's longest-running television game show and has been a longtime supporter of children's charity Variety.
His brother Mark Leishman is a radio host.