Watch: Spectacular new discoveries captured in video of the Kermadec Arc

Underwater volcanoes in the Kermadec arc have leaked their secrets to Kiwi and German scientists studying the hydrothermal systems in the thriving marine area.

A four-week expedition on board the RV Sonne from Auckland to Noumea focused on the 2,500 kilometre stretch between the Bay of Islands and Tonga.

"We've seen things we've never seen before,"  said GNS Scientist Dr Cornel De Ronde.

"We discovered some animals in places we've not seen them before and we also discovered some very high 20-metre chimneys full of copper, lead, zinc and gold."

Upon the investigation of the seafloor, the team also discovered fluid being pumped out of the vents to be around 312 degrees Celsius, a new record high.

The Kermadec arc is made up of roughly 80 volcanoes and all except four are located beneath the surface.

German and Kiwi scientists have just arrived from a research trip to the islands. Source: 1 NEWS

"It's a very special place, it marks the collision, if you like, of two tectonic plates," Dr de Ronde told 1 NEWS.

"One goes beneath the other one and it causes part of the crust to melt, which forms volcanoes which have these hydrothermal systems."

The research trip was a joint collaboration between Germany and New Zealand as part of a long-standing agreement in Scientific Research.

"We've got a very good relationship and the German scientific establishment is obviously very strong and well-equipped," said Paul GoldSmith, Minister of Science and Innovation.

"New Zealand has an exclusive Economic zone (EEZ) that is one of the largest in the world. We've got this massive territory of ocean around New Zealand which we only have a very limited understanding of. So all the help we can get form countries like Germany is very important."

The RV Sonne is a research vessel commissioned by the German Government to study the marine biology of the Pacific Ocean and it spends much of its time in New Zealand waters.

An open day will be held on Wednesday on Auckland's Princess wharf for members of the public who want to tour the ship, before it sets sail on Thursday with a new research team on board.