Catherine, Campbell's mother, posted the photos on to Mount Maunganui Notice Board 20+ Facebook group.
"What the hell? Who takes a cat up the mountain? You're not even allowed dogs up there," she said.
"It's ridiculous," she laughed.
Dogs are not allowed on the popular track.
The backpack may not be common but "In a Nutshell" pet carrier capsules can be bought. They are described as being fashionable and designed with comfort in mind.
They come In a range of colours, are dirt resistant, with breathing holes on the front and side, and a "comfortable strap".
Meanwhile, in another case of cats turning up in unusual places, yesterday a cat attended part of a Tauranga City Council meeting.
The moggy belonged to drug addiction worker Darryl Wesley, who presented to the meeting about his opposition to legalising cannabis.
The human rights commission disagrees with the treaty principles bill, cocaine and cannabis are increasingly being used in the workplace as we get sun for the weekend.