Nuclear power should be "part of the mix" of Britain's energy supplies in the future, Alistair Darling has said.
Ministers say nuclear power will cut carbon emissions
An energy White Paper will be published on Wednesday - Tony Blair has already said he supports replacing Britain's ageing nuclear power stations.
The Observer newspaper reported that his successor Gordon Brown will also support the plans this week.
Trade and Industry Secretary Mr Darling told the BBC that renewable energy sources alone would not be sufficient.
He told BBC One's The Politics Show that it was not sensible to rule out nuclear power which could help to fight climate change and to make sure Britain does not become dependent on imported gas and oil.
But asked whether reports that up to eight new power stations would be built in the next 15 years were true, he said: "I don't have a firm number in my mind as to the actual proportion or the number of power stations.
"What I do know is that you do need a mix.
"The trouble with renewables is they're very good in providing you with low carbon electricity generation, but of course on very hot days or very cold days, if the wind doesn't blow, then you would have a big problem.
"That's where nuclear has provided a base load of electricity for many years now."
He said he would also be announcing changes that would encourage more renewable energy.
The White Paper was originally due to be published in March, but the government was told to consult again after a legal challenge by environmental campaigners Greenpeace.
The government says its energy proposals will cut carbon emissions by between 19 and 25 million tonnes by 2020.
Mr Blair told MPs in January: "It is extremely important that we as a country make sure our energy supply is secure for the long term - that, in my view, needs a diverse supply of energy".
But the Green Party has condemned the plans as "astronomically expensive" and "dirty and dangerous" while Greenpeace say it is misguided.
Greenpeace's Stephen Tindale has accused Mr Blair of being "fixated" with nuclear power, adding: "Anything substantial in this review that supports clean green energy will be fatally undermined as long as Blair remains prime minister."
But the Observer on Sunday reported that this week Mr Brown, who will replace Mr Blair as prime minister at the end of June, would face down his own party's anti-nuclear MPs to back a new generation of power stations.