No more nuclear power stations should be built as they are "hopelessly uneconomic" and would create vast amounts of waste, say the Lib Dems.
Lib Dems say nuclear power is 'diverting' resources
Environment spokesman Norman Baker said any expansion "would divert essential funding" from renewable sources, such as water and wind farms.
The government is conducting a review of the future of the UK's energy.
Tony Blair has said more nuclear power stations could be used to help reach targets on pollution.
The Lib Dems led an opposition debate on nuclear power in the Commons on Tuesday.
Mr Baker said: "A new generation of nuclear power stations should not be part of the future UK energy mix.
"Nuclear power is hopelessly uneconomic and the commissioning of a new generation would effectively result in a nuclear tax on every household to pay for them.
"A new generation of nuclear power stations would generate vast quantities of nuclear waste and divert essential funding away from energy efficiency and renewable sources of energy."
A Mori poll has suggested 54% of people would accept new nuclear power stations if they helped fight climate change.
But 78% of the 1,500 people interviewed for the University of East Anglia thought renewable technologies and energy efficiency were better ways of tackling global warming.
And 63% believed the UK needed a combination of energy sources, including nuclear and renewables, to ensure a reliable supply of electricity.
Energy Minister Malcolm Wicks is leading the government review of UK energy policy, with proposals due by the summer.
In the Commons debate, Mr Wicks said it was not a "nuclear review" but the future role of civil nuclear power had to be considered.
'No single answer'
Nuclear already part of the energy mix, accounting for about 19% of current electricity generation, said Mr Wicks.
"But the current generating plants are ageing and most are scheduled to be decommissioned over the coming 15 years or so.
"By 2020, therefore, it is estimated that only about 7% of our electricity might come from nuclear as things stand."
Mr Wicks said waste, costs and safety had to be examined.
"We also need an evidence-based look at what new nuclear technologies can offer," he said.
"And even if new nuclear could provide some of the answers it can never be the whole picture."
Claims that building new nuclear plants would rule out everything else were "total nonsense", he added.
MPs later rejected the Lib Dem call to oppose a new generation of nuclear power plants by 309 votes to 63.