Sebastian Langton's "best buddy" Rango used to ride to work with him on his motorbike and join him at cafes on weekends.

One day the tabby cat went missing, never to be found. Mr Langton decided he wanted to avoid the heartache again but was underwhelmed by products on offer.

"The crushing moment was never getting to find out what happened to Rango and that gave me the anger and motivation to stick it out and a year later we'd come up with the smallest and lightest GPS [pet] tracker in the world," he said.

An owner can locate their pet with a click on an app, and set a safe zone, being alerted any time the furry friend goes outside the boundary.

Known as the Pod, the tracker has sold nearly 5000 units for Mr Langton's Pod Trackers company in a year. The British born Sydneysider, 34, was in Canberra this week ahead of its first launch into a physical shopfront, available from November in more than 200 Petbarn stores nationally.

Using a combination of GPS, WiFi and cellular technology, pets can be tracked interstate or even overseas, with the tough waterproof unit fitting to any collar. Owners can access data showing the route their pet took.

It's not the only pet tracker on the market but Mr Langton said the 29 gram unit was at least six grams lighter - and half the size - of any competitor.

In pet-loving Australia, where pound retrieval fees can be hundreds of dollars, there was an estimated 4.2 million pet dogs and 3.3 million pet cats in 2013, the Animal Health Alliance said. Mr Langton, a former sailor, said one in three pets went missing in their lifetime.

No wonder Mr Langton was confident he was sitting on a billion-dollar business, with wider tracking possibilities in his sights.

"The scope isn't just pets, it could be kids, luggage, cars," he said.

But even with a couple of replacement felines known as Smokey and The Bandit, the young businessman said his original motivator was never forgotten.

"Every unit has For Rango engraved in it - I miss him every day," he said.