The executive has not yet revealed the underspend

In previous years ministers have announced in June the amount of money left over in departmental budgets.

However, the total underspend for the year 2002/03 has not been released, prompting the Conservatives to accuse the executive of attempting to hide the figures.

The executive dismissed the claims saying that this year's figures had not yet been finalised and audited, following the recent Holyrood election campaign.

It described as "speculation" reports in the Scotsman newspaper that the figure for the last financial year would be �500m.

The total sum, described as end of year flexibility (EYF), has been announced in June for the past three years.

In 2000 the EYF was �435m, but this rose sharply to �718m the following year, before falling to �643m in 2002.

Scottish Tory leader David McLetchie called on the cash be used to cut business rates and to scrap graduate endowment payments instead of introducing free universal eye and dental checks, which Labour and the Lib Dems decided on in their Partnership Agreement.

He said: "This is an astonishing cover-up by the parties of the Scottish Executive, who are clearly too busy squabbling with one another to actually make the announcement that they have once again failed to spend the vast amounts of money taken from Scottish taxpayers.

The figures have still to be finalised, and when that has happened we have a duty to the public to make sure they are properly audited. Finance department spokesman

"Instead of arguing about where to waste this money, they should be finding ways to give it back by cutting taxes on individuals, families and businesses."

A finance department spokesman dismissed the cover-up claims as "utter nonsense".

He said: "The reason why the EYF was not announced in June is because this is the first year that there has been an election to the Scottish Parliament, which involved a period of purdah during the campaign, as well as negotiations for the Partnership Agreement.

"The figures have still to be finalised and when that has happened we have a duty to the public to make sure they are properly audited.

"We expect to make a statement shortly after the return of parliament, which is the proper place for this information to be announced."