Andy Hodson, from NSW's South Coast, chose Rocky from a pen on the Gold Coast 19 years ago when Rocky was a four year old. He was a runaway dog, who had no documentation - vets estimated his age by examining his teeth.

Mr Hodson said Rocky had chosen him, and selected his name too.

When he first adopted the dog, Mr Hodson didn't have a ball to throw. He threw a rock, which Rocky instantly fetched.

"He won't chase a ball, he just loves rocks," he said. "He chose the name Rocky, and he has been my rock.

"The only reason I'm breathing is because of him.

"He has looked after me for years, and now it is my turn."

The oldest living dog recorded online is 22 years and 2 months. Rocky is now 23 years old. Mr Hodson said 23 was roughly 160 years old in 'dog years'.

Mr Hodson could do a DNA test in America to more accurately determine Rocky's date of birth, but hasn't pursued this expensive course of action

The pair have driven around Australia one and a half times in their shared 19 years.

"He's my codriver and my navigator," Mr Hodson said.

He said Rocky was the perfect travelling companion - he listened well, didn't take up too much space, and was patient and loyal.

"If I was with a lady it would be overcrowded, but with this little dude it's absolutely perfect," he said.

However, like many relationships, the pair have had highs and lows.

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Two years ago, Rocky suffered a stroke. Mr Hodson said it was a really scary moment. Three days later, he relapsed. The vets at the time said the prognosis was dark.

Two years later, Rocky is bouncing around in the sun, full of life.

"He's a survivor," Mr Hodson said. "He just survives. He is a rock.

"I've been blessed to have him as my dog.

"I hope he is here for another 23 years, and I wouldn't even be surprised."