Above-ground work on the world's first one-kilometre tall tower will start next week in Jeddah, Saudi Arabia, a report said.

Construction on the Kingdom Tower is scheduled to begin on April 27, said reports. Construction is scheduled to complete in 63 months.

The construction of the $1.2bn skyscraper will be overseen by joint UK project managers EC Harris and Mace.

Kingdom Tower will be the centrepiece and first phase of the  $20bn Kingdom City, a mixed-use district to the north of Jeddah.

The developer, Jeddah Economic Company, has not yet confirmed the exact height of the tower, but has indicated it will be over 1km tall. The current tallest tower in the world is the 828m-tall Burj Khalifa in Dubai.

The piling work on the project was completed in December by contractor Saudi Bauer.

The project’s architect is US-based Adrian Smith + Gordon Gill Architecture and the main contractor Saudi Binladin Group.

It is expected to use half a million cubic metres of concrete and around 80,000 tons of steel, said a report in the Independent.

The finished building will cover a total area of over 500,000 sq m and have 200 floors.  There will be 59 elevators, including five that are double deckers. Those that take visitors to the observatory will travel at 10 metres per second, it said.