The government's support for expanded nuclear energy plans and simultaneous hints at a deferral of the 2p increase in fuel duty have prompted criticism from the Conservatives.
Shadow chancellor George Osborne said the government was failing to provide the "stable and certain" tax policies required in times of economic difficulty.
Yesterday prime minister Gordon Brown made clear his support for an expansion of nuclear energy in Britain beyond existing plans. His call for a "more ambitious" programme came in response to concerns about high energy costs, caused by the need for a "better balance" between supply and demand.
The week's headlines have been dominated by high energy prices and how to react to the problem. Yesterday a meeting between UK oil chiefs, Mr Brown and chancellor Alistair Darling resulted in agreement that reforms of the taxation system for North Sea oil are required.
Mr Darling also hinted the 2p rise in fuel duty, due to be implemented from this October, may be deferred. His comments mirrored those of justice minister Jack Straw, who said the pre-Budget report could be used to delay the hike.
Responding to this news, Mr Osborne said: "Pleading with international oil companies to increase production is all well and good but surely the simplest thing that Gordon Brown could do now is say that he will not go ahead with his ill-conceived plans to put taxes up on family cars."
"It's difficult to see how Gordon Brown and Alistair Darling could make the government's position on road tax and fuel duty more complicated, but today they succeeded."