Barrack Heights family reunited with beloved Boris four months after disappearing

Boris may have looked scared and emaciated after dropping half his body weight during his disappearance, but Tom Dahne said he could see in his friend's eyes he was happy to be home.

"His inspiring tale of survival and the importance of never giving up ... I hope this will give hope to a lot of other pet owners out there that have a missing pet," said Mr Dahne, a full-time carer for his son Brendon.

The nine-year-old originally disappeared on August 23 after escaping the yard and being hit by a passing car. That was the last time he saw Boris before the shock of near-death sent him running for the hills.

"It was like a clip, but it rolled him over ... he just bolted, he's not used to traffic, and we couldn't catch him," Mr Dahne said.

"We spent the next 10 weeks straight out looking for him."

Mr Dahne and his partner Leanne did all they could to ask for the community's help in finding Boris, with posts about the lost guard dog going viral.

A dedicated Facebook page was set up amassing nearly 1000 members, while hundreds of printed paper flyers were being posted around the Illawarra, in people's letter-boxes and further afield.

Despite only brief sightings and no confirmed images of Boris, Mr Dahne did not wane in his quest to find his mate.

Then this week Andy Bridge was mowing lawns in Warrawong and noticed a large dog in "poor health" cowering under a house and wouldn't come back out, which was news to the resident.

It turned out to be Boris, and Mr Dahne could not be more thrilled to be reunited on Tuesday.

"I thought this would be another dead-end lead like all the other ones we followed, you have high find hope and go out there then get shot down, it's been an emotional roller-coaster ride," Mr Dahne said.

"People have been emotional, you know, for a dog that they don't even know. It's overwhelming, the outpouring [of relief he's alive] ... it grabbed a lot of people's hearts."

Boris was taken to the vet immediately after the reunion and is now on a regime to get his health back on track, but the pooch is happy to be home.

Reannon Mendez of the Animal Welfare League Illawarra branch said this "remarkable survival story" has sparked immense joy throughout the community and is a "testament to the compassion and determination present within our region".

"This story also highlights the importance of sharing concerns for animal welfare," Ms Mendez said.

"Boris's journey serves as a reminder to remain vigilant, to never underestimate the resilience of our furry friends, and to unite in protecting and caring for them."