Derek Mackay is facing a potentially explosive choice between teaming up with the Tories or Greens to pass his budget through the Scottish Parliament.
The finance secretary needs the support of another party for spending proposals to be set out in February as the SNP doesn’t have a Holyrood majority.
For the last three years, the party has relied on help from the Scottish Greens.
But Patrick Harvie’s MSPs have said the price of their support this time will be a “climate emergency” budget expected to involve a commitment to scrap a £6billion scheme to dual the A9 and A96 to free up cash for public transport.
Agreeing to the radical carbon-cutting plan would be hugely controversial and business leaders, including
Scottish Chambers of Commerce boss Liz Cameron, have warned it could threaten the economy.
The Tories have now said they will back an SNP budget as long as Mackay promises not to increase tax while giving more money to the NHS, police and higher education.
Shadow Conservative finance secretary Murdo Fraser has said increased Barnett formula funding from Westminster will cover the cost of the spending on public services.
He also wants more drug rehabilitation beds, refunds for NHS staff who have to pay at hospital car parks and £50million for Police Scotland.
Fraser said: “With the spending announcements already made for areas such as health and education in England, we expect there to be substantial Barnett consequentials coming to the Scottish Government.
“The two areas that we view as priorities for this budget are measures to grow the Scottish economy and support for vital public services.”
Harvie has challenged Mackay to work with his party to tackle climate change “head on” or side with the “toxic” Tories.
He said: “It’s no surprise the Tories want to ignore the climate emergency while lowering taxes for their friends.”
Mackay is expected to set out his draft budget on February 6.
A spokeswoman said: “We are speaking to all opposition parties ahead of the budget.”
