Public opinion is divided over the development of a new generation of power stations, according to a poll.
Supporters say nuclear power cuts greenhouse gas emissions
Some 48% of the 1,004 people interviewed for the Guardian opposed an expansion, while 45% supported it.
Tony Blair has promised a decision on whether the government will give the go-ahead for building new nuclear stations by the summer.
A group of Labour MPs is to mount a campaign urging the prime minister not to build more nuclear power stations.
The MPs, led by former minister Alan Whitehead, are launching a manifesto to promote investment in renewable energy, saying the government would be taking a "dangerous leap with nuclear".
But some reports say Mr Blair sees building more nuclear power stations as the only way to meet future energy needs while sticking to environmental targets.
His official spokesman said last month: "The prime minister's view is that we need to look at all the options and everybody knows that is what we are going to do."
Supporters of nuclear power say it will cut greenhouse gas emissions.
The polling group ICM interviewed a random sample of 1,004 adults by telephone between 15 and 18 December for the Guardian survey.