Chancellor Alistair Darling is set to say "hard choices on public spending" are necessary once Britain has recovered from the financial crisis.
In a speech on Government plans to "reprioritise" spending, Mr Darling is set to say he "won't flinch from difficult decisions".
But he will stop short of announcing what services are likely to be cut to rebalance the public finances in a keynote lecture to the Chambers of Commerce at Cardiff City Stadium.
The Chancellor will set out the Government's determination "to never risk the fiscal sustainability of our economy".
He will say: "This will mean, as Gordon Brown and I have already made clear, hard choices on public spending. We won't flinch from these difficult decisions. But we will always be guided by our core values of fairness and responsibility."
In a bid to separate the Government's plans from those of the Tories, Mr Darling will add: "There are those who have used this crisis to justify widespread cuts in public expenditure without spelling out their economic and social impacts."
On Saturday, G20 finance ministers meeting in London agreed economies should be supported by government spending until they have recovered. But when recovery had been established, all countries should "rebuild their fiscal strength", Mr Darling will say.
"The global economic background means that spending will be tighter everywhere - all the more reasons for ensuring that the frontline comes first. Today I have made the case for active government. Properly targeted public investment can and must make a difference.
"But this means making choices and setting priorities. It means more efficiency, continuing to reform, cutting costs, public and private sectors working together. Essential steps if we are to secure jobs and increase prosperity for the future."
Mr Darling will tell delegates, mainly owners of small and medium-sized businesses, that private endeavour and a functioning market are "key components" of a healthy economy but not enough on their own.
Read More
MORE ABOUT