A colossal breakthrough has been made in the research of giant squid with a Japanese film crew capturing the first video of the elusive creature deep in the Pacific Ocean.

The footage, which will be aired on Discovery Channel later this month, has excited scientists around the world as it is the first time a giant squid has been filmed alive.

Japan's National Science Museum succeeded in filming the creature at a depth of about 630 metres in the Pacific Ocean and followed it in a submarine to a depth of about 900m.

The squid came in about three metres long - nearly half a metre longer than the colossal squid (an immature female) on display in Wellington's Te Papa. The colossal squid is slightly shorter than the giant squid but has a larger, heavier body.

According to the Discovery Channel, the three-man crew carried out about 100 missions and spent close to 400 hours in the tiny submarine to track the squid from a spot about 15 kilometres east of Chichi Island in the north Pacific Ocean.

On Japan's public broadcasting channel NHK, museum researcher Tsunemi Kubodera said it was the ultimate reward for a lengthy quest.

"It was shining and so beautiful," he said.

"I was so thrilled when I saw it first hand, but I was confident we would because we rigorously researched the areas we might find it, based on past data."

Kubodera said the creature had its two longest arms missing, and estimated it would have been eight metres long if it had been whole.

He said the two successful sightings of the squid - last year and in 2006 - were both in the same area about 1000km south of Tokyo.

Scientists have suggested it could be a major habitat for the species.

Little is known about the species, which is thought to be the inspiration behind the mythological sea creature the Kraken, which, according to Nordic legend, dragged entire ships and their crews to the bottom of the ocean.

The beast featured in the 1870 Jules Verne classic Twenty Thousand Leagues Under The Sea, and, more recently, in 2006's Pirates of the Caribbean: Dead Man's Chest movie.

Giant squid are thought to grow up to 10m long, but live at depths that humans generally can't explore.

- © Fairfax NZ News