Vast deposits of rare earth minerals, crucial in making high-tech electronics products, have been found on the floor of the Pacific Ocean and can be readily extracted, Japanese scientists said on Monday.

"The deposits have a heavy concentration of rare earths. Just one square kilometer (0.4 square mile) of deposits will be able to provide one-fifth of the current global annual consumption," said Yasuhiro Kato, an associate professor of earth science at the University of Tokyo.

The discovery was made by a team led by Kato and including researchers from the Japan Agency for Marine-Earth Science and Technology.

They found the minerals in sea mud extracted from depths of 3,500 to 6,000 meters (11,500-20,000 ft) below the ocean surface at 78 locations. One-third of the sites yielded rich contents of rare earths and the metal yttrium, Kato said in a telephone interview.