In a report published today, Holyrood's finance committee warns that Scotland's budget could be set on the basis of out-of-date tax forecasts by the independent Office for Budget Responsibility.
MSPs on the cross-party committee call on the Scottish and UK governments to provide greater clarity on how the tax changes will be applied.
Under tax reforms in the 2012 Scotland Act, Holyrood will set a portion of income tax from April 2016.
The UK Government will cut income tax rates by 10p across all bands and reduce the Scottish Government's "block grant" - its budget - accordingly.
The Scottish Government will then set its own income tax rate to make up as much or as little of the shortfall as it sees fit.
However, the reduction in the block grant will be based on OBR tax forecasts made a year in advance, sparking concerns over their reliability.
Finance Committee Convener Kenneth Gibson MSP said: "We recognise that considerable effort has been put in by both the Scottish and UK governments in implementing the financial provisions of the Scotland Act 2012.
"However, we believe it is essential that there is effective parliamentary scrutiny of the implementation process and, in particular, the way in which the UK Government will adjust Scotland's block grant to take account of the new financial powers."