A mai-mai is typically a simple wooden-framed structure, often lined with corrugated iron, providing a place for duck hunters to take shelter.
However, The Country's Andrew Thompson said this mai-mai took it to another level.
He gave the mai-mai a 10 out of 10 when he took a tour through it.
"I have seen a few in my time but nothing like that," said Thompson, a duck hunter himself.
"From the outside it looks nondescript, but it is like a hobbit's hole, and just gets bigger and bigger inside.
"The average maimai might just be a small room, somewhere to sit and get out of the rain with a bit of comfort. Maybe with a BBQ or bar, and a shooting gallery with seats. This just takes it to another level."
The shelter had even been wrapped in a plastic membrane, with grass and trees growing on top of it.
The group of duck hunters started building the mai-mai in 2009 and improved it each year. They had even recorded the process in a book.
"It is never in its final incarnation, and each year they go there and make improvements," Thompson said.
It could seem an unusual project, but in Southland mai-mai had a long and proud tradition.
"Duck hunting in Southland is an absolute religion," Thompson said.
"The opening weekend of the duck shooting season is the most important day on the social calendar.
"Duck hunting happens in other parts of the country – but nothing like Southland. Nobody takes it as seriously as these guys. And mai-mai are very precious, there is a lot of tradition around them.
"On a weekend a group of mates might get a sober driver and go on a mai-mai crawl, visiting their mates at each one. It is a huge social migration around these areas, and is a lot of fun.
"This one just take it to the next level, but it is symptomatic about how important it is to the region."