New financial powers already agreed for Scotland will be a "considerable challenge" to implement, a Holyrood committee has warned.
MSPs are concerned about the level of information provided by the UK and Scottish governments to help with the provisions of the Scotland Act 2012, including a new rate of income tax.
The new tax rate - due to come into force in April 2016 - means the UK Treasury will deduct 10p from standard and upper rates of income tax in Scotland and give MSPs the power to decide how to raise cash.
But Holyrood's Finance Committee said there is a lack of clarity about forecasts, particularly with the UK's Office for Budget Responsiblity (OBR).
Considerable work will be needed by both governments to agree proposals to adjust the block grant allocated to Scotland by Westminster, the committee found.
MSPs also have concerns about "wildly optmistic" OBR forecasts for the land and building transaction tax (LBTT), which replaces stamp duty land tax in April 2015.
They said forecasting for a new landfill tax must be transparent and open.
Finance Committee convener Kenneth Gibson MSP said: "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.
"We will continue to closely monitor the accuracy of the OBR forecasts and will take evidence from the chair of the OBR on an annual basis."
The report concludes: "The committee recognises that there is a considerable challenge for both the UK Government and the Scottish Government in implementing the financial provisions of the Scotland Act 2012.
"Nevertheless, it is essential that there is effective parliamentary scrutiny of the implementation process.
"The committee is concerned about the level of information being provided by the two governments as the negotiations progress.
"At the same time, the committee welcomes the commitment of the Scottish Government to consult with the Scottish Parliament on the adjustments to the block grant and emphasises the need for sufficient time to be made available to allow the committee to carry out effective scrutiny of the proposals."
A Scottish Government spokeswoman said: "We welcome this report and the recognition of the Scottish Government's work to take forward the financial provisions of the Scotland Act.
"We agree that the Scottish Parliament and people require greater clarity over changes to the allocation of the block grant and the Scottish Government is working actively with HM Treasury to achieve that.
"While welcome, the tax raising powers to be transferred to the Scottish Parliament through the Scotland Act represent a missed opportunity, only giving Parliament control over an additional 17% of Scotland's revenues. With full fiscal and economic powers the Scottish Parliament could do more to realise Scotland's full economic potential."
A UK Government spokesman said: "We continue to work closely with the Scottish Government to implement the new and unprecedented financial powers in Scotland Act 2012.
"The Act increases the flexibility available to Scotland as part of the Union to pursue its own tax and spending policies while retaining secure and stable block grant funding.
"This is a further clear example of devolution delivering for Scotland."