The National Oceanic and Atmospheric Administration has clarified that no island composed of debris from the Fukushima tsunami is heading towards the U.S. coast of California.

"There is no solid mass of debris from Japan heading to the United States."

"At this point, nearly three years after the earthquake and tsunami struck Japan, whatever debris remains floating is very spread out. It is spread out so much that you could fly a plane over the Pacific Ocean and not see any debris since it is spread over a huge area, and most of the debris is small, hard-to-see objects," NOAA wrote on its Marine Debris blog.

The agency was forced to issue the clarification after it released a map that showed a solid mass material floating in the world's open oceans. Its trajectory was supposedly headed for the U.S., between California and Hawaii.

But while the tsunami that crippled Japan's Fukushima nuclear power plant in 2011 gave off 5 million tonnes of floating debris, 70 per cent of these have sunk off somewhere out there in the wide open seas.

A beach littered with tsunami barriers, wreckages of cars and other debris is seen at the coastal area of the evacuated town of Namie, with cranes and chimneys of the crippled Daiichi nuclear power plant in the background, in Fukushima prefecture in this September 23, 2013 file photograph. To match Special Report FUKUSHIMA-WORKERS/ REUTERS/Damir Sagolj/Files

"While there likely is some debris still floating at sea, the North Pacific is an enormous area, and it's hard to tell exactly where the debris is or how much is left. A significant amount of debris has already arrived on the U.S. and Canadian shores, and it will likely to continue arriving in the same scattered way over the next several years," the agency said.

"As we get further into the fall and winter storm season, NOAA and partners are expecting to see more debris coming ashore in North America, including tsunami debris mixed in with the 'normal' marine debris that we see every year."

However, with its presence confirmed, concern is growing the debris contains unwanted or undesired organisms.

"We're finding that all kinds of Japanese organisms are growing on the debris," John Chapman, a scientist at Oregon State University' Marine Science Center, told Fox News. "We've found over 165 non-native species so far.... we'd never seen [some of these species] here, and we don't particularly want [them] here."

"We have been seeing more and more," Glen Spain, Northwest regional director of the Pacific Coast Federation of Fishermen's Associations, said.

"The major hazards of this stuff is that it can carry invasive species, like the pier that washed up. And the bigger stuff can be a navigational hazard."