French nuclear giant Areva said Tuesday it is suspending building work at several sites in France, Africa and the United States, one day after forecasting a 1.6 billion ($2.1 billion) euro loss.

The investment freeze came amid mounting controversy over job losses at the majority state-owned group, with a minister denying claims from unions that a restructuring plan would see 1,200 posts cut in France next year.

Areva halted "capacity extensions" at its reprocessing plant in La Hague, in northern France, at its Melox factory in the Gard in the southwest and at two sites attached to its Tricastin power plant in the south.

Work has also stopped on extensions to the Eagle Rock enrichment plant near Idaho Falls in the United States and to uranium mines in Bakouma in the Central African Republic, Trekkopje in Namibia and Ryst Kuil in South Africa.

In total, Areva hopes to reduce its new capital investment by a third to 7.7 billion euros between 2012 and 2016.

Later in the day, the firm was due to announce a broad restructuring aiming to make a billion euros in savings per year from 2015. Between 1,200 and 1,500 job losses are expected in Germany, which is abandoning nuclear energy.

But the threat of job losses in France has generated controversy.

Unions representing Areva workers, which were briefed by management on Monday, claim that a freeze on new hires would see 1,200 retiring or leaving workers not replaced next year. They have demanded the plan be dropped.

But Industry Minister Eric Besson, speaking to Europe 1 radio on Tuesday, dismissed this figure as "fantasist" and insisted the government would prevent mass redundancies in France.

On Monday, Areva had warned its 2011 operating loss may top 1.6 billion euros ($2.1 billion) after Japan's Fukushima nuclear disaster hit the value of its uranium mining assets.