"They reckon he'd been in there for about a week," Station Officer Shane Dudley said.
St John Ambulance territory manager John Stretton said a member of the public called police when they noticed the man's parched gardens and overflowing letterbox.
Police went to the house and heard the 81-year-old man moaning and calling out to them.
He had fallen in the bathroom and couldn't get up. Paramedics found him to be very cold and dehydrated.
Firefighters were called at 8.40pm to assist.
"He wasn't very well," Mr Stretton said. "It shouldn't happen in a developed society like ours, but unfortunately it does," Mr Stretton said.
A hospital duty manager said yesterday the man was in a stable condition.