Plant & Food Research funded the $1.9 million tank, which is located at its research centre in Port Nelson. It's 16 metres long and holds 190,000 litres of water that can be moved at horizontal speeds of up to 1.5 metres per second.
Scientists say it will enable the fishing, aquaculture and marine engineering industries to test how new innovations will cope in New Zealand's ocean conditions.
At the official opening, Minister for Oceans and Fisheries Shane Jones said the flume tank was a gamechanger in an industry where more collaboration was needed.
"We've hit certain limits with land-based activities and the ocean is largely empty and there is no shortage of space around Te Waipounamu to grow more fish."
It's hoped the tank will be used by scientists, researchers, engineers and entrepreneurs from a range of organisations and businesses to grow the marine and seafood sector.
"If the industry is serious about protecting its social licence and expanding more economic output from a relatively defined resource, then they themselves have to invest, they themselves have to work with scientific pioneers and not purely look to the Crown for ongoing funding but spend some of their own dough."
"Our point of difference is that it would be a mobile system, so that would mean you could move your fish farm to make best use of the temperatures around the coast, to avoid anything you needed to avoid and therefore provide the fish with the best environment and the best production outcomes."
Chief scientist Richard Newcomb said mobile farms could help to manage the effects of warmer ocean temperatures, which can result in finfish mortalities.
"Currently all of the open ocean aquaculture structures are static structures but we think there is an option to look at mobile structures that would mitigate some of the environmental concerns but also give us the flexibililty to move away from the weather or marine heatwaves."
He said without a flume tank, scientists had to rely on computer modelling before doing ocean testing.
Seafood New Zealand chief executive Jeremy Helson said the new tank was a significant investment in the marine industry.
"There's nothing of this scale in New Zealand so this is a fantastic opportunity for the seafood industry and hopefully for other industries that have an interest in the marine environment."
There is scope for the flume tank to be used to test developing technologies - including renewable marine energy generation and marine robotics.