The 72-year-old, who led the Wallabies to their 1991 World Cup triumph in England and later coached both Leicester and Bristol, is reported to have complained of chest pains at home yesterday before being taken to a Sydney hospital.
It was in hospital that he suffered the heart attack, and emergency treatment saw him survive the scare.
Dwyer told Fairfax Media: "I'm doing well. I feel fine.
"I had a cardiac arrest whilst I was in the emergency ward at Bowral Hospital.
"I was on a monitor and had the doctor with me and (then) I had the arrest.
"They gave me the electrical charge straight away and I came straight back.
"Talk about being at the right place at the right time. If it had have happened at home, I would be dead."
There was swift reaction from the rugby world to Dwyer's fright.
Former Australia centre Tim Horan, who played in Australia's World Cup final win over England at Twickenham 21 years ago, wrote on Twitter: "Wishing Bob Dwyer a speedy recovery from a heart attack. Not many can combine being a great coach and a great person."
A more recent Wallaby, Wendell Sailor, wrote: "Just like to wish Bob Dwyer a speedy recovery after suffering a heart attack one of the real gentleman. #getwellbob"
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