Alistair Darling has ruled out a "giveaway Budget" as he put the finishing touches to the pre-election package he will deliver on Wednesday.
Better than expected tax and borrowing figures have given the Chancellor more leeway than anticipated - up to £12 billion according to experts.
But despite the political pressure of a general election just weeks away, he insisted the focus would be on tackling the UK's record deficit.
"This will not be a giveaway Budget," he told the Mail on Sunday, saying the Government had to "continue to live within its means".
Among measures reported to be set for inclusion are a £1 billion fund to kick-start investment in green transport and energy projects and extra help for the long-term unemployed.
Mr Darling is also thought to be considering whether to postpone a planned 3p rise in fuel duty.
It emerged on Saturday that he will use the Budget to confirm support for some form of global levy on banks - if international agreement is reached.
However Tory leader David Cameron went further, promising to introduce such a measure unilaterally if necessary in order to protect taxpayers' interests.
Mr Darling is unlikely to announce other new taxes though, and has already ruled out detailing spending cuts at this stage in line with plans to stimulate growth.
The Tories want to move faster on tackling the deficit, which the Government has pledged to halve in four years, but Labour insists that would "wreck" the recovery from recession.