Spending plans will be debated by MSPs next week
Opposition parties are lobbying Scotland's finance secretary as he prepares this year's draft budget.
John Swinney said his spending plan would protect frontline public services such as schools and hospitals.
But Labour insisted the Glasgow Airport rail link project must be reinstated before its support is given.
The Scottish Liberal Democrats want pay cuts for top public servants and the Scottish Tories want more transparency over how public money is spent.
The draft budget for 2010/2011 will be debated at Holyrood on Wednesday.
Mr Swinney said: "The challenges facing the public finances are well known and responsibility for addressing them is shared between government and the parliament.
"In the face of the budget reductions imposed on us by the Chancellor next year and the forecasts of significant spending constraints in the medium term, we must work collectively and decisively to agree a Scottish budget for next year that meets the needs of the people of Scotland."
He called for "positive" engagement among political parties, and added: "I have made clear on many occasions that I am open to constructive propositions from others but I have also made clear that we must be realistic about the resources that are available to us."
Labour finance spokesman Andy Kerr said a budget was needed for "the economy, jobs and homes". But he added that it was clear the SNP was failing in the task.
"Instead of delivering for Scotland, they're teaming up with the Tories to introduce cuts that will undermine the economy's recovery," said Mr Kerr.
John Swinney says frontline public services will be protected
Tory leader Annabel Goldie said it was time for the "government to open its books".
She added: "The Conservatives are demanding the SNP government now commits to publishing online details of all spending over £25,000.
"This would be a transparency revolution in public spending."
Liberal Democrat finance spokesman Jeremy Purvis MSP said he wanted pay cuts for top public servants and better opportunities for young unemployed people.
He added: "The published Budget Bill does not yet do all that. It is the same bill as first drafted back in the autumn.
"That is why it is critical that the government makes changes to its plans to get our support for the budget."
Green co-leader Patrick Harvie MSP said the budget was still not a credible response to the economic pressures Scotland faced, nor did it take advantage of the environmental opportunities available.
Independent Lothians MSP Margo Macdonald wants extra cash to fund apprentice stone masons in Edinburgh.
The plan offers "jobs for life" and aims to protect traditional skills in a city with a large proportion of historic stone buildings, she said.