Finland has approved plans to build the world's first permanent nuclear waste storage facility, which would stock 6,500 tonnes of uranium for about 100,000 years underground. Citizens in western Finland have also agreed to the proposal, the Finnish government has said.

The centre-right government gave the green light to Posiva Oy waste management group to set up the first-of-its-kind facility, which will be 450 metres beneath the surface. The entire construction and maintenance of the project is estimated to cost around €3.5bn (£2.4bn, $3.6bn) and the plant would be operational by 2023.

"The government granted Posiva Ltd a licence to construct a spent nuclear fuel encapsulation plant and disposal facility at Olkiluoto," the government said in a statement. Meanwhile, Finland's Economy Minister Olli Rehn, said at a press conference: "This is the world's first authorisation for the final repository of used nuclear waste."

He added: "Finland is an international pioneer in nuclear waste management, which also obliges us to take care of matters responsibly and safely in future. Finnish expertise also provides us with commercial opportunities in developing nuclear waste management in other countries."

At first the nuclear waste would be deposited in copper containers which would then be sealed with bentonite clay and stored underground. It is estimated 270,000 tonnes of nuclear waste has been lying around across the world with no permanent solution so far as the material could remain toxic for thousands of years.

Posiva, jointly owned by Finnish nuclear utilities Fortum and Teollisuuden Voima Oyj, expects to begin the construction of the waste management site in 2016. The Olkiluoto site was chosen in 2000 and was formally approved by the Finnish parliament in 2001.

Posiva said that a similar project is underway in Sweden, but it will take a longer time to become operational. The waste management firm's CEO Janne Mokka said: "The construction licence that has now been granted for our final disposal facility for used nuclear fuel is a significant achievement for us, our owners and our entire personnel. This pioneering project is important not only for Finland, but also on a global scale. It is the first project entering into construction phase in the whole world."