At a glance, it's no more than your average garage.
An unassuming black frame around a hole in the wall on West St in Eden Terrace; its red 'CITY KICKBOXING' sign obstructed from view of those approaching on foot by the foliage of a large tree.
But beyond the roller-door and up a short narrow staircase, the thundering clap of skin on pads echoes around the room. The floor and walls are lined with wrestling mats. A boxing ring sits in the middle of the room, with a weights station on the other side behind a curtain of punching bags. The pungent stench of stale sweat hangs thick in the air, only getting thicker throughout the day as some of the country's best combat sports stars put in work.
It's been 11 years since Eugene Bareman and Doug Viney opened the gym. Both active fighters at the time, they wanted somewhere they could work while focusing on their training.
It didn't quite go to plan.
"We were fighting and we worked other jobs," Bareman explains to the Herald. "We kind of thought to ourselves well if we open a gym then we can just be in the gym all day.
"It sucked heaps of our time away. Our original intention was to free us up a little bit, but it actually didn't free us up - it made us more busy, so we were off the ball there.
"The original intention definitely didn't work out."
But what started as an excuse to train more has become a combat sports haven. Bareman and Viney, along with fellow trainers Mike Angove, Tristram Apikitoa and Chanel Niumata, are now the driving force behind some of Australasia's top talent.
Among their stable is Kiwi UFC stars Israel Adesanya, Dan Hooker – both fighting in Las Vegas this weekend - and Shane Young; and boxers Junior Fa – WBO Oriental Heavyweight Champion - and Baby Nansen, who recently fought at Madison Square Garden on the undercard of the Vasyl Lomachenko-Jorge Linares world title fight.
"The gym has a wealth of coaching knowledge," Bareman says.
"We all have input into all the fighters. That's what helps develop the gym. We started like every other gym with just a whole lot of fighters that were beginners and then we built them over 11 years. It's 11 years of work to get to the point we are now."
And it's not just Kiwis making the most of the gym's expertise. Australian UFC fighters Alexander Volkanovski and Rob Wilkinson spend plenty of time at City Kickboxing, and recently American boxer Danyelle Wolf made the trip down under to train at the gym.
Bareman, who has 48 fights under his belt, was hoping to get to 50 before he officially retired, but training the competitors they have at the gym is a time consuming gig, leaving no time for his own fight-focused preparation.
He says the development of the gym has been thanks to a snowball effect - with good coaches comes good fighters, and when you have good fighters, others want to get into to the gym and train with them. And the fact that it's a small sport in a small country helps - with fighters never having to worry about access to trainers.
"You've got to have a group of high quality guys who can push you, and a lot of gyms are struggling to get the numbers to put a good team of guys together that push each other," Bareman explains. "This gym's got a good group of fighters – professionals – always training, all year round and even a lot of gyms in Australia can't offer that."
Volkanovski, who fights out of Windang, New South Wales, has been a common visitor to City Kickboxing, after an existing relationship with one of their fighters - kickboxer Brad Riddell. The featherweight, who holds a 17-1 professional record and was unbeaten in four fights in the UFC, says the opportunity to push himself with a group of top-level athletes makes a massive difference.
For the past two months, the 29-year-old has been in fight camp with Adesanya, Hooker and Young – with all four stepping into the octagon within a matter of weeks. Young took a win in Singapore late last month, Adesanya and Hooker fighting this weekend in Las Vegas, and Volkanovski fights the following week in Boise, Idaho.
"I'm all about training with as many different bodies as you can and the different styles, and obviously all levels as well," Volkanovski says. "Some people are going to be strong at one thing, some people are going to be strong at another, so I like to really feel out all aspects of the game so there's no surprises come fight night.
"No better place than to do it here."
To get the day's top sports stories in your inbox, sign up to our newsletter here