Britain's reliance on nuclear energy should increase over the next two decades, business secretary John Hutton has told The Financial Times.
Sizewell B, the UK's newest reactor, was built in the 1980s
Mr Hutton announced plans in January for a new generation of nuclear plants to replace the UK's 10 ageing stations.
But Mr Hutton told the FT he would be "disappointed" if the proportion of energy generated by nuclear did not rise above the current 19%.
He pledged to "keep our foot down on the pedal" for more nuclear power.
Mr Hutton says private operators will be expected to meet the full cost of building nuclear plants, decommissioning and disposing of waste.
But he has said no "artificial cap" would be put on the proportion of electricity to be generated from nuclear power or any other source of "low carbon" energy.
Asked by the FT if he wanted the share of electricity contributed by nuclear to increase above 19%, he said: "That's the ambition we should have...I'd be very disappointed if it's not significantly above the current level."
The government's nuclear plans could be still be subject to a legal challenge from Greenpeace, which successfully challenged an earlier government review backing nuclear power in the High Court.
It claims research shows that even 10 new reactors would cut the UK's carbon emissions by only about 4% some time after 2025.
The nuclear industry believes it can get the first new plant on-stream by 2017.