Plans for wide-ranging budget cuts in the public sector are "patchy and lack urgency", a cross-party committee of MSPs has warned.
Members of the Scottish Parliament's finance committee also said the efforts of the public sector to tackle the issue were inadequate.
They have called for leadership from ministers, MSPs and the public sector.
A review panel set up by the Scottish government to consider where the cuts should be is due to report in July.
The UK government has already unveiled £6bn of cuts before its emergency budget this month.
Describing the issue as "the most significant challenge" faced by both the Scottish government and Scottish Parliament since devolution, the committee said Scotland's public service budget cuts could be "drastic".
It has asked the government for more detail on expected job losses, how ministers plan to maintain universal benefits, such as free eye tests, and whether certain areas are to be protected from the cuts.
Urging politicians and the public sector to hold "realistic" discussions on the issue, committee convener Andrew Welsh said it was time to spell out the detail of where the axe would fall.
The SNP MSP added: "We therefore call on the Scottish government to set out more fully the principles that will inform its approach to developing its spending proposals.
"This would demonstrate real leadership by setting out spending choices in an open and transparent manner, and would also provide committees with a much clearer understanding of the Scottish government's intended approach."
Mr Welsh also said that, given the scale of the challenge and the likely impact on jobs, it was essential MSPs and the Scottish government began working together.
The Scottish government said the findings underlined the case for financial responsibility being transferred to Scotland.
It added: "We welcome this report, as an important contribution to the work already underway to deal with that spending cuts challenge, both next year and in the long term.
"On that basis, the Scottish government has set up an independent budget review panel to dispassionately consider options and make recommendations by the end of July.
"Those findings will inform debate and discussion as we prepare the 2011-12 budget."