The budget for the London 2012 Olympics could rise beyond £9.3bn.
By Mihir Bose
BBC sports editor
A study of Olympic costs carried out after Gordon Brown became Prime Minister says there is a 20% chance of the current budget falling short.
But the Government says it is confident the £9.3bn figure - which is four times higher than the cost named in London's bid for the Games - is "robust".
Olympics minister Tessa Jowell will make a written statement on the 2012 budget to Parliament on Monday.
She is expected to reflect the government's confidence in the £9.3bn figure, but it is understood she will not refer to this study.
Although the Government study says that the chance of a budget increase may be slim, the study recognises the high risk of the project, which must be completed on time with the Games to start on 27 July, 2012.