SNP promises that independence will deliver "Scandinavian style" public services have been branded, "castles in the sky" by the Scottish Secretary.
Alistair Carmichael said to replicate the social models of countries like Norway, Sweden and Denmark in Scotland would require significant tax increases.
He said the public must be told how these services will be paid for.
Mr Carmichael is debating with Finance Secretary, John Swinney today and he warned the public to beware of "assertion and omission".
He said: "Nowhere is this more true than of their much-publicised admiration of the Scandinavian social model.
"There is of course a great deal that is positive about Scandinavia. It is perfectly legitimate to admire strong social services and high levels of equality.
"But it is not legitimate to assert that an independent Scotland could have the same while omitting the hard choices that would be required to get there.
"The higher levels of public spending found in Scandinavia require higher taxes to pay for them. Much higher."
He said official Government Expenditure and Revenue figures showed Scots paid 36.7% of their income in tax, while in Norway citizens pay 42.2%, in Sweden they pay 44.2%, and in Denmark they pay 48.1%.
Mr Carmichael added: "Over recent months, Denmark has been cited over and over as an example to follow.
"But this would involve each Scot paying £3,100 more tax a year."