In an 18-day expedition of the deep sea floor, the scientists collected several geological samples and sea floor creatures for analysis, the New Zealand Press Association said.

The Geological and Nuclear Sciences Ltd (GNS) exploration was the country's first in a manned submersible, and investigated the Brothers volcano 1,800 meters below the sea.

"We saw scores of chimneys, some six meters tall, each containing thousands of tonnes of metal," GNS project leader Cornel de Ronde said.

Fluids were pumping out of chimneys at 300 degrees Celsius forming dense plumes of black smoke at one of the sites, Ronde said.

Minerals in the chimneys included iron, copper, lead and zinc.

The biological samples they took included shrimp, scale worms, crabs, eel-fish, limpets, and tube worms - the first time the species had been recorded in New Zealand territorial waters.

The scientists believe that up to 30 percent of the creatures they collected might never have been investigated before.

Among the creatures recovered using the submersible's robotic arms were "colonies of heat-loving micro-organisms that may have potential future applications in pharmaceuticals, in bioremediation of contaminated sites, and in biomining", GNS said in a statement.

Ronde hoped the joint New Zealand-Japanese expedition could be repeated. "It has also opened the door for further collaboration with the Japanese."

--Indo-Asian News Service