Hollywood film director James Cameron looks set to become a Guinness World Record holder for the second time, after reaching the bottom of the Mariana Trench, the deepest point in the oceans.

According to reports, the movie maker travelled at 26,700 feet an hour (about 5 mph) in his one-man submarine Deepsea Challenger in order to dive seven miles below the ocean's surface.

The Trench, situated just off the coast of the Pacific island of Guam, measures a massive 120 times larger than the Grand Canyon and is more than a mile higher than Everest is tall.

Guinness World Records is currently awaiting evidence before ratifying a record, although Cameron's feat certainly puts him in line for the title of deepest manned dive, equalling the record set by US Navy Lt Don Walsh and Swiss oceanographer Jacques Piccard in 1960.

The Walsh/Picard mission saw the pair spend 20 minutes on the ocean floor in a deep-sea submersible calledTrieste.

Cameron could also lay claim to the deepest solo dive as well as the deepest tweet ever sent after sending a message declaring that he had reached the ocean's deepest point to his followers on Twitter.

With the sea bed illuminated by the lights on his submarine, Cameron was able to see out on to the desolate underwater landscape from a small window, describing the sea floor as "devoid of sunlight, devoid of any heat, any warmth".

The pressure was so great that it squeezed the height of his submersible vehicle by three inches.

Little in the way of life was immediately visible with the only creatures perceptible near the bottom being tiny shrimp-like arthropods. Cameron said further exploration would be required to discern what other organisms might live at the ocean's surface.

"When I got to the bottom ... it was completely featureless and uniform," he said. "My feeling was one of complete isolation from all of humanity. ... More than anything, [it's] realizing how tiny you are down in this big, vast, black, unknown and unexplored place."

The 57-year-old already holds the record for the director of most movies to gross over $1 billion, while his 3D science fiction epic Avatar holds seven world records including highest box-office film gross.

"Ocean trenches really are our planet's final frontiers," said Guinness World Records Editor-in-Chief Craig Glenday, "and Cameron's fantastic voyage - the first in more than 50 years - will help us all learn more about the mysteries of this uncharted world.

"His passion for the ocean, and his dedication and drive to succeed, makes him a record-breaker who will rightly take his place among the world's greatest explorers."

Cameron's dive was part of a joint scientific expedition by Cameron, the National Geographic Society and watch makers Rolex.

He says he plans to return to the Trench in the near-future for further exploration as well as taking samples from the ocean's surface floor in order to aid scientific research.