Green MSPs have told the First Minister they will only support the Scottish Budget next year if there is "meaningful progress" in reforming local taxation.
Co-convener Patrick Harvie said the "groundwork" for scrapping the current council tax system had already been done and there was now "cross party recognition" the present arrangements must end.
Budget deals with the Greens, who have six MSPs at Holyrood, have allowed the minority SNP administration to pass its tax and spending plans for the last two consecutive years.
But Mr Harvie said changes to local government taxation would now be required before his party would back another Scottish budget.
In a letter to Nicola Sturgeon the Green MSP claimed successive Scottish Government budgets had "squeezed local government harder than UK austerity has cut the national settlement".
And he made clear that Greens "are not willing to allow the national budget process to become an annual rear-guard action against local funding cuts".
He stated: "Local tax reform is an opportunity to put local services on a sure financial footing.
"To ditch a system of taxation that asks poorer households to pay proportionally more, to adopt a fairer system of land and property taxation, to empower local decision-making, and to shift tax from income to wealth where inequalities are greater."
While Mr Harvie conceded the full replacement of the council tax system would "require time for consultation, legislation and implementation", he stressed the "initial steps must be taken in order for progress to take place over the rest of the parliamentary session".
Suggestions put forward by the Greens include devolving or partly devolving control of business rates to councils, setting a target for the proportion of council spending which is raised locally, and minister committing to indicative multi-year funding deals for local government to help councils plan ahead better.
Mr Harvie added: "A number of other options for reform exist, which can be implemented either from 2019/20 or shortly after.
"They include ending the practice of council tax ratecapping, in lieu of longer term reform proposals; introduction of a vacant and derelict land levy, as we have previously proposed; enhancing the ability of councils to invest by giving them the power to acquire land at current use value; and the creation of new fiscal powers at local level, such as the power to create environmental taxes or a visitor levy."