Chancellor of the Exchequer Alistair Darling will deliver his second Budget on April 22.
The statement is expected to include further Government measures to help Britain recover from recession.
Many observers believe that Mr Darling will be forced to revise his prediction, made in November's Pre-Budget Report, that the UK economy would return to growth in the second half of this year.
Mr Darling's PBR forecast has come increasingly under question by economists who expect the recession to run beyond the middle of this year and possibly carry on into 2010.
In a gloomy quarterly forecast delivered on Wednesday, Bank of England Governor Mervyn King warned of "deep recession". The Bank made a dramatic downward revision to its growth forecast - predicting that the economy could shrink by as much as 4% in the summer and remain in recession for the bulk of 2009.
Mr King said the prospects for economic growth and inflation remained "unusually uncertain", suggesting new types of emergency action would be required soon as cuts to the interest rate - now just 1% - lost their bite.
The Treasury and 10 Downing Street have repeatedly fended off demands for an update on their expectations for the prospects of the economy, by saying that they make economic forecasts only in the Budget and Pre-Budget Report.
The April 22 date for the Budget is later in the year than any previous Budget held since Labour came to power in 1997.
Its timing means it will come after the crucial April 2 summit of the G20 group of the world's leading economies in London, at which Prime Minister Gordon Brown hopes to forge international consensus on tackling the global economic crisis.
The delay in the spring economic statement will also allow Mr Brown and Mr Darling more time to assess the impact on the UK economy of their fiscal stimulus measures, as well as the 800 billion dollar package being introduced by US President Barack Obama, who is expected to make his first UK visit since entering office to attend the G20 meeting.
