"She's a really good dog, so easy to train," senior constable Ross said. "We don't usually have many females so she's certainly one of the best."
The new Mako harnesses are tailored for the dogs to provide essential protection for their main organs from stabbing or slashing.
Senior constable Ross said the harness was essentially bringing the dogs into line with the type of protection an officer had.
"It's almost equivalent to the stab resistant vests we have ... but it allows us to keep the dog's agility and speed - its major strength."
He said Deja had been injured before, including having her head kicked and stomped by an offender.
"She was hurt but ... she bounced back. We're a team and when we ask a dog to bite, it's last resort. We have all tactical options available to us ... it's hugely challenging for me and Deja but hugely rewarding."
He said turning up to a call and having Deja find a runaway was confirmation he's in the right job.
"That for me is the most rewarding. When you're tracking someone and you have no idea where they could be ... there are times we wouldn't find them without the dog. Deja is trained and conditioned for these situations so it's good to have that protection."
There are five police dogs based in Palmerston North. Deja and the others are all purebred German Shepherd's, specifically bred at the dog training centre in Trentham.