"I could not believe it. Rod landed at 10.05am and rang me from the car at about 10.30. He said he could not wait to have a beer with me.
"Then soon Dave rang me from the car and told me what had happened. It's devastating.''
The 74-year-old's family is on its way to Queensland to be with their father and husband, News Corp reported.
A spokesperson confirmed that Cricket Australia was aware Marsh had suffered a medical episode, and wished him the very best while being treated.
Former Australian paceman John Hastings tweeted: "Thinking of the Marsh family and the wider cricketing community. Such a loved man by so many. Sending love and prayers. ️Sad news today."
Marsh scored 3633 Test runs and claimed 343 catches during a stellar international career that included a stint in Kerry Packer's World Series Cricket.
The wicketkeeper also scored 4412 runs for Western Australia in the Sheffield Shield over 15 seasons.
Following his retirement in 1984, Marsh continued contributing to the cricket community as a coach, commentator and national selector.
He was inducted into the Cricket Australia Hall of Fame in 2005 and the ICC Cricket Hall of Fame in 2009.