Ex-soldier Jacob Leezak says he was born to be with dogs.
He runs the Canine Behaviour Expert Dog Psychology Centre just outside of Sydney.
There are at least 30 dogs at any time, some of them abandoned, others rescued before they were euthanised for aggressive behaviour.
New Zealand film maker Eryn Wilson's documentary Dog's Best Friend, follows Jacob and his fiance Jennah for several weeks as he works with dogs, showing how he and his pack of dogs teach new dogs to interact naturally.
The doco will be shown at the New Zealand International film festival. Find out more here.