Shadow Scottish secretary Margaret Curran hit out at the Holyrood administration for spending taypayers' cash on the adverts.
She said data obtained using Freedom of Information revealed the Government paid out £84,160.80 for billboard adverts across the country over the period from December 2 to December 15 - just after First Minister Alex Salmond launched the white paper on independence.
Ms Curran blasted: "While families across Scotland are struggling, the SNP are spending taxpayers' money to promote their plans for separation.
"In two weeks in December, they spent £6,000 a day putting up posters across Scotland."
She had raised her "concerns about the Scottish Government's expenditure in relation to the referendum" during Labour's Scottish conference in Perth
She told activists there: "In the space of two weeks in December last year the Scottish Government spent £84,000 of taxpayers' money on billboards in constituencies across Scotland - £6,000 a day was spent of taxpayers money advertising for the Yes campaign effectively.
"There's better ways to spend that Government money, and our people need it."
Scottish Labour deputy leader Anas Sarwar said: "I think when we look back on this referendum in five years' time or 10 years' time one of the great scandals that will be exposed is the amount of time, money and effort put in from the Scottish Government machine."
He added: "This is not a government, it's a campaign. What we need is a government that is focused on the real issues facing this country and actually changing people's life chances."
Meanwhile Labour leader Johann Lamont accused ministers of having a "relaxed view of what public spending is for".
She said: "It's not just the money, although the money is part of it, it's the roadshows, it is the time and energy of our cabinet ministers who should be thinking about how to make this place a better place, who are campaigning round the country."
A Scottish Government spokeswoman said: "There is a clear precedent for such a public information campaign in the 1997 devolution referendum. The Scottish Government has always said that it would set out its proposition for independence to inform voters ahead of the referendum.
"Scotland's Future is the most comprehensive and detailed blueprint of its kind ever published, not just for Scotland, but for any prospective independent country, and has met with such a huge level of demand, which is testament to the appetite for information that exists around the referendum debate.
"It is only right that there should be a public information campaign to ensure that as many people as possible are able to have access to the arguments and make an informed decision on 18 September."