The UK Treasury said measures in the Spending Review announced on Wednesday mean Scotland will get an additional £2.4 billion of cash - with more than half (£1.3bn) of this related to the pandemic.
That comes on top of the £8.2bn the Scottish Government has already received to help deal with the impact of coronavirus.
But Ms Forbes accused the Chancellor of cutting her capital spending budget at the same time as this is being increased in the rest of the UK.
Reacting on Twitter to Mr Sunak's statement, she said the "Spending Review illustrates the damaging economic impact of Covid-19 - which is precisely why we need to invest in recovery".Ms Forbes added: "Behind the Chancellor's headline £27bn increase in UK capital expenditure, Treasury docs show a cut to Scot Gov's capital budget by 5 per cent in cash terms."
She further claimed a pay freeze for many public-sector workers "makes very little economic sense at a time when we should encourage spending and consumption".
The Finance Secretary said: "In just over a month, the end of the transition period will see Scotland removed from the EU and yet the Spending Review hasn't replaced in full, as promised, EU funding for our communities, research institutes or rural economy.”
Ms Forbes will set out the Scottish Government's draft budget for 2021/22 on January 28.