Northern Secretary Peter Hain has apparently contradicted recent comments by Prime Minster Tony Blair by saying the case for Britain increasing its nuclear energy capacity is not proven.
Speaking on BBC radio, Mr Hain warned the public would not accept a "gung-ho" approach to nuclear power in the formulation of policy on Britain's future energy needs.
He said there should be a "massive ramping up" of renewable energy.
But Mr Blair said earlier this week said he would take "a lot of convincing" that Britain could supply its energy requirements without nuclear power.
It was his strongest hint yet that next month's energy review will give the green light to a new generation of nuclear plants.
Such a move is sure to spark more protests from Ireland on the political and environmental front.
Minster for Environment Dick Roche expressed his displeasure when Mr Blair first indicated last May that he was inclined towards expanding nuclear power production to compensate for dwindling fossil fuel supplies.
The State has been pursuing the UK through international courts over the Sellafield nuclear reprocessing plant in Cumbria, northwest England.
The plant has had numerous safety scares and leaks and it is widely accepted that its contamination of the Irish Sea has led to higher than ususal instances of cancer among prople living on Ireland's eastern seaboard.
But just weeks before a high-level review of Britain's future energy requirements is published, Mr Hain said: "The case for nuclear has still to be proven and we'll see what the energy review produces.
"I am very clear that the lights have to be kept on, in 10, 15, 20 years time when this problem of supply really seriously hits us ... and if nuclear is the only way to fill it, well I'll reluctantly have to accept that.
"But if we get to that point without a massive ramping up of renewable energy then I don't think the public will support it."
Additional reporting PA