"In principle we are ready (to build the plants) but the political conditions must be right," an EON spokesman told AFP.
"Our plan hasn't changed. We have always said we would wait for the British government's decision," expected this summer, on the future of nuclear energy, he added.
"We must await the government's decision and look at it in detail," a spokesman for RWE said for his part.
German newspapers meanwhile suggested that the two companies, which set up a joint venture to take part in Britain's expansion of nuclear power when it was announced in 2008, now see the plans as too costly.
Officially, the companies expect to invest €16 billion ($23 billion).
But Germany's decision to abandon nuclear energy by 2022 has cooled investor confidence and nuclear investments in Britain are expected to take years before showing any profits.
Conservative Prime Minister David Cameron's coalition government, in power in Britain since May 2010, is reviewing its energy policy to encourage investment in nuclear and wind power and getting rid of old fossil fuel plants.