The Slovak branch of environmental organisation Greenpeace said on Tuesday it will launch a legal challenge against plans by Slovakia's biggest electricity producer to complete two blocs of a nuclear power plant.

Greenpeace said it would challenge state institutions for not carrying out an environmental impact assessment of Slovenske Elektrarne's plans to complete two reactors at an existing nuclear power plant at Mochovce in the west of the country.

"Greenpeace has for a long time criticised the fact that the power plant will be built on the basis of construction approval given in 1986 without an accompanying environmental impact assessment," said Greenpeace organiser Karel Polanecky. It will demand an evaluation according to current procedures is carried out, he added.

Slovenske Elektrarne, in which Italian power giant ENEL has a 66-percent stake with the remaining shares owned by the state, took the decision last year to complete work on the two mothballed blocs by 2013 with investment expected to total around 1.81-184 billion euros (2.37-2.41 billion dollars).

Work on the two blocs was stopped 16 years ago, shortly after the collapse of the former communist regime and ahead of Slovakia's independence in 1993 following the split of Czechoslovakia.

The new capacity forms a fundamental part of the Slovak government's plans to boost electricity production to power its booming economy with the country facing the prospect of becoming a net electricity importer from next year.