In Germany, athletes been playing the game for more than 60 years and the sporting body has up to 5000 members.
In this country, just a few hardy Auckland University students and members of Auckland's Fins Underwater Hockey Club have taken the plunge, forming New Zealand's first underwater rugby competition last year.
Christian Staubach (30) is a former national German underwater rugby representative.
Now living and working in Wanaka, Staubach is happy to promote his sport, although it cannot be played in Wanaka because there is no diving well.
However, he believes more New Zealanders should take it up.
"For me it is a kind of lifestyle, the best sport ever. You get addicted to the possibilities of what's happening under water," he said.
It is a very fast game so most of the time players might only be holding their breath for 15 seconds at a time.
"But a big problem for a goalkeeper is the penalty. This can be 45 seconds long and you have to stay the whole time under water," Staubach explained.
Staubach grew up in Karlsruhe in south Germany, where he worked in information technology.
Swimming and life-saving have been his life.
But he got bored with swimming on top and switched to underwater rugby, eventually playing for Germany for six years.
In the early days of the sport, it was known as underwater polo but the name was changed to better reflect the contact nature of the game, he said.
The leading nations in underwater rugby are Finland, Sweden, Norway, Denmark and Germany.
Staubach's last outing for Germany was in 2007, when he was goalkeeper at the world championships in Italy.
As a spectator sport, the three-dimensional game is not an easy one to watch, unless someone videos it or there are pool windows.
Staubach said a friend had described it as a "pool full of piranhas".
Serious injuries are rare.
"We can get hand or shoulder problems but this is because of lifting or tangling with someone. It is not because we are hitting the ground," he said.
Underwater rugby
At a glance
Gear: Togs, goggles or mask, flippers, ball, two buckets.
Venue: A pool, preferably 3m-5m deep, 8m-12m wide and 12m-18m long.
Players: Six in the water, six reserves.
Ball: A heavy, round gym ball filled with salt water, sanded to improve grip; it should sink 1m per second.
Concept: Score a try by putting the ball in weighted bucket on the bottom of the pool; ball carrier may be tackled; the ball can be passed or carried underwater; the ball cannot be passed over the surface of the water.
Holding your breath: Usually up to 20sec. Goal keepers up to 45sec.
