Scottish ministers have warned of a spending squeeze
The Tories have urged Scottish ministers to prepare a stand-by budget in case further emergency cuts have to be made after the UK General Election.
The party said it would only back Scottish spending plans which were realistic about the need to save money.
The call came ahead of the first of several parliamentary votes on the new Scottish budget due next week.
Labour is to vote against the plans, partly in protest at the cancellation of the Glasgow Airport rail link.
Meanwhile, the Liberal Democrats have called for a 5% pay cut for the highest earners in the public sector.
Scottish Finance Secretary John Swinney has yet to show his hand on the issue of which demands he may meet - although he has stressed the squeeze in public spending means tough choices being made.
Ministers have already announced the cancellation of the Glasgow Airport rail link, saying they had £500m less to spend because of Westminster efficiency cuts - a claim disputed by the opposition.
But the SNP government has insisted vital public services would be protected.
The Tories now want Mr Swinney to prepare for the prospect that the UK government may order further immediate cuts - whoever is in charge after the election.
Meanwhile the Greens, whose two MSPs were instrumental in the initial rejection of the last Scottish budget, before it was passed on the second attempt, said the latest spending plans failed to deliver.
"As it stands, this budget continues with the SNP's piecemeal, bureaucratic and means-tested approach to household energy costs, tinkering at the edges not tackling the problem," said its leader Patrick Harvie.