TOKYO, February 22, 2012 (AFP) - A Japanese construction firm claimed Wednesday it could execute an out-of-this-world plan to put tourists in space within 40 years by building an elevator that stretches a quarter of the way to the moon.

Obayashi Corp claims it could use carbon nanotube technology, which is more than 20 times stronger than steel, to build a lift shaft 96,000 kilometres (roughly 60,000 miles) above the Earth.

The company said it would carry up to 30 passengers at a time and travel at a speed of 200 kilometres per hour for a week, stopping off at a station at 36,000 kilometres.

Tourists would stay there, but researchers and specialists would be able to travel all the way to the end, said Satomi Katsuyama, the project's leader.

"Humans have long adored high towers," she said. "Rather than building it from the earth, we will construct it from the space."

However, while Obayashi says the plan could work, there are presently no estimates for the cost of the structure, nor any idea where to build it, or who would pay for it.

Obayashi is just days away from completing work on Japan's tallest structure, the Tokyo Sky Tree, which will stand 634 metres (2,080 feet).

The tower will serve as a digital broadcasting antenna as well as a sightseeing attraction that allows uninterrupted views of the Japanese capital and beyond.

"We were inspired by construction of Sky Tree," which will open for business in May, she said. "Our experts on construction, climate, wind patterns, design, they say it's possible."

When Obayashi is not drawing up plans to conquer space it works on a number of projects from building corporate headquarters, bridges and power plants to renovating ancient temples.

Among its portfolio are the Dubai Metro in United Arab Emirates, Universal Studios Osaka, Japan, and Stadium Australia, which was used for the Sydney Olympics.