A young boy has been told he could face up to three months in jail if he returns to a Warehouse branch in west Auckland in the next two years.

Twelve-year-old Kyan Hatcher was on Sunday issued with a trespass notice during a visit to the store with his father, and told he's not allowed to return to the Henderson Warehouse until September 2019.

The notice comes after CCTV cameras captured Kyan and a friend building a fort behind the store's shelving a few weeks prior - though nothing was said to either of them at the time.

Instead it was on his return that a security guard pulled him aside and took both he and his Dad into a backroom, where they were issued the notice, told not to come back and then escorted out of the retailer.

In that time, Kyan was told he could face a prison sentence if he tries to return before the trespass notice expires.

The boy's father Blair Hatcher told Newshub that while he didn't agree with what his son was doing, "the punishment was a bit extreme".

His wife Johanna agreed, telling Fairfax the response to her son's fort-building was "ridiculous".

"If anything he should have got a warning about playing with things in their shop but definitely not a trespass notice and being made to feel like a criminal," she said.

"He felt so terrible and like a really bad person."

The Warehouse told Fairfax it was aware of the incident, and planned to speak to Kyan's family.

Employees also explained that their reaction came because they believed Kyan and his friend were attempting to sleep in the store overnight, presenting an obvious security risk.

Newshub has approached The Warehouse Group for comment.

Newshub.