The EU has indicated that the pan-European tests will assess nuclear plant exposure to potential earthquakes, tsunamis, terror attacks and power cuts, amongst other variables.

Exact criteria have yet to be determined however, with industry reacting angrily to Oettinger's apparent pre-judgement of the test results.

"It's too early to say that some plants will fail," Christian Taillebois, director of external relations with the European Atomic Forum (FORATOM), told this website. "If the criteria is to automatically close some plants this would be a bad thing," he added.

Experts in the field were also taken by surprise. "Perhaps he has some special information that we don't," said Stephan Kurth, a nuclear scientist with the Oko-Institut, Germany.

He agreed however that some of Europe's older nuclear plants were less safe than their more modern equivalents, pointing to Germany's Biblis A and B plants, and the plant at Brunsbuttel, a boiling-water model similar to those in Japan.

News that China had decided to suspend approval of new nuclear power stations also shocked the industry late Wednesday, with Beijing announcing plans to carry out checks at existing reactors and those under construction.

China is currently building 27 new reactors - about 40 percent of the world total under construction - with the country's latest five-year plan, agreed on Monday, containing extensive proposals to push the sector forwards.

On Monday, Germany called a halt to production at seven plants of its plants following the accident at Japan's Fukushima Daiichi plant where technicians continue in their desperate attempts to cool overheating fuel.

Japan's crisis was now in the "hands of God", Oettinger told MEPs on Wednesday, sending stock markets into a spin. A day earlier he said Japan was facing an "apocalypse".

Berlin's decision to nominate the former Baden-Wuerttemberg (BW) regional president for the EU position surprised many in late 2009, with a leaked diplomatic cable providing an insight into Chancellor Angela Merkel's reasoning.

"The move was not the promotion of a valued colleague as Merkel's allies sought to portray it. Rather, Oettinger's increasing loss of party support in BW compelled Merkel to push Oettinger out to protect her support base there," reads the confidential US cable, dated December 2009 and released by WikiLeaks.