Opposition parties in Scotland have called for a cut in council taxes after it was revealed that local authorities failed to spend £800 million last year.

Two of the smallest councils were found to have the highest amounts in reserve.

While taxes rose by five per cent, Scotland's 32 councils collectively hoarded £839 million, including Shetland at £379 million and Orkney at £185 million.

Alastair MacNish of the Accounts Commission described the figures as "high".

Conservatives argued that, taken alongside the £550 million in unpaid bills, a council tax reduction was possible for this year.

"This highlights the fact that the debate over what we call the tax misses the point," said finance spokesman Brian Monteith.

"It is the level of council tax that causes so much avoidance pain.  With 15 per cent of council income coming from council tax, the scope for cuts is massive.

"Labour taxes are too high and the Lib Dem and SNP local income tax plans would cost thousands of Scots more of their hard-earned money.

"They are the high tax, low return parties.  Scotland has suffered enough."

A spokesman for Cosla, the local authority umbrella group, defended the figures.

"That kind of level of reserves shows that councils are taking a prudent approach to financial management," he said.

"Councils have to take account of unforeseen circumstances and areas such as pensions, which require fairly good reserves to ensure we are not caught out at the end of the financial year."

But SNP finance spokesman Fergus Ewing disagreed.

"This money may be intended for a rainy day, but for hard-pressed pensioners it's already raining," he said.

"This will prove to be a PR disaster for councils.  They now have to explain to Scotland's pensioners, and all council tax payers, why their bills went up yet again this year."