A 57-year-old adventurer from Tokyo hopes to complete a 22,000-km trek by dog sled across the Arctic from central Siberia to eastern Greenland in July, more than five years after setting out on the journey.

Tokyo adventurer Kazuo Kojima drives his sled dogs across the Arctic.

If successful, he would nearly double the current long-distance record.

Kazuo Kojima, a top musher, said he embarked on the trip because he wanted to follow the route supposedly taken by ancestors of the Inuits, a group of American Indians, to reach North America about 20,000 years ago.

In March 1997, Kojima and his team, including mushers from Canada, Russia and the United States, set off from Irkutsk, central Siberia. They traveled intermittently, taking advantage of periods of good weather.

The team endured ordeals along the way including being detained by Russian authorities on suspicion of spying and getting stranded near the Bering Strait waiting for ice to thaw.

Nevertheless, Kojima pushed on and said he was happy to make first contact with the Inuits. In May, Kojima and his 52-year-old Canadian teammate reached northern Canada after traveling some 2,500 km.

"When we were held by the Russian authorities, I became reluctant," Kojima said. "I'm surprised we've come this far. I think this is due to everyone's support."

Kojima hopes to reach Ammassalik, Greenland, in late July, breaking the long-distance record for a dog-sled journey. That record was set in 1976 by another Japanese, the late Naomi Uemura, who logged some 12,000 km on a solitary journey from Alaska to Greenland.