Steve Irwin's father Bob recalls the last moments he shared with his son.

‘Crocodile hunter’ Bob Irwin has recalled the final moments he shared with his late son Steve, who died in 2006.

The 77-year-old’s heartbreaking account comes from his new book The Last Crocodile Hunter: A Father and Son Legacy, in an extract exclusively shared with news.com.au.

As Irwin writes, the pair had been sitting around a campfire at the end of a research project in Cape York when his son opened up.

Aching and weary, Steve was said to have admitted he felt as though he’d nearly reached his “expiry date”.

“He was struggling physically because he’d really knocked himself around and he rarely gave himself any reprieve from his injuries,” Bob wrote.

A photo posted by Bob Irwin Wildlife (@bobirwinfund) on Oct 1, 2014 at 3:48am PDT

Steve, then 44, went on to share how he wanted to spend more time at home and with his young daughter Bindi.

Bob said his son was littered with scars after a lifetime of continuously pushing his body to the edge.

“In his lifetime he’d been snapped, gnawed, clawed, bitten, savaged, jumped on, whacked — you name it. He had scars all over him,” he wrote.

“No two fingers were the same; each one had either been broken, split or chomped.”

The elderly Irwin shared how he nursed a niggling feeling that his son knew something was approaching.

“You never expect that’s the last time you’re ever going to see your son, but I certainly had a feeling he sensed something was about to happen,” he said.

The last goodbye ended with a handshake and a wish that his son would "take it a bit easier".

"See ya later, Bob," Steve replied.

News of his son's death came via a phone call in the middle of an otherwise unremarkable day.

"It's incomprehensible to wake up without a care in the world and go about your day, as carefree as normal, and then get a life-altering phone call like that," he wrote.

"Steve was my everything. My friend. My strength. My mirror image."

Steve Irwin died on September 2, 2006, after a stingray pierced his chest during filming for an upcoming documentary on deadly animals.

The Last Crocodile Hunter: A Father and Son Legacy was published on October 25 by Allen and Unwin.