Energy group Atel said it has submitted plans to the government for a new plant near Olten in northern Switzerland, not far from the German border and the existing Goesgen facility.

But the plan is not without its opponents, and the umbrella group "No to Nuclear" -- made up of 28 different groups including the Socialist Party -- also announced it would seek a popular referendum on the issue.

Switzerland built its last nuclear facility in 1984.

The country observed a moratorium on any more nuclear projects for all of the 1990s, and in 1998 the government proposed winding down its nuclear energy programme altogether -- though this was rejected by a popular referendum in 2003.

The government is now calling for a progressive build-up of nuclear energy given the looming expiry of delivery contracts from neighbouring countries.

Switzerland currently produces 38 percent of its electricty from nuclear plants.