Queenstown's Mountain Scene newspaper approached Andy on Tuesday night, after a reader's tip-off.
The 20-year-old, who didn't want to reveal his surname, said he had been living in the tree house for three weeks.
He said he had tried to contact the landowner but failed. Naively, he thought the owner wouldn't mind.
"It's an amazing view to wake up to every morning and a bit of an adventure. They were throwing the material out from work so I wanted to put it to good use."
Andy said he took a week off work to build the tree house. It has carpet, insulation and a hammock.
Clark, also Australian, gives the Department of Conservation and Queenstown police both barrels.
He says DoC should fence the track. And he says when he complained to police yesterday afternoon he was told no crime has been committed.
"They said they don't want to be sending officers into a situation where they don't know what they're going into.
"They told me to go instead - a man in his 60s. What are the police for?"
A police spokeswoman says issues between landowners and neighbours are generally considered "civil matters".
But police can get involved if trespassed people refuse to leave.
The tree house is the second built on the down-low in Queenstown recently.
Glazier Glenn Raymond built a hut on a willow island in Lake Wakatipu.
Queenstown's council regulatory boss Lee Webster says unlawful builds are the landowner's responsibility.
- Mountain Scene