Mr Gibson made the comment on Tuesday as MSPs discussed the forthcoming 2025-26 budget with auditor general for Scotland, Stephen Boyle, and other officials.
Mr Boyle said more clarity was needed on the government’s capital spending and its plans to reorganise the public sector.
Both the finance committee and Audit Scotland have issued warnings about the affordability of government spending, with the auditors calling for “fundamental change” in November.
Mr Gibson noted that Audit Scotland had delivered an “excoriating” report and was critical of the government’s transparency in a submission to his committee, which was received just before Christmas.
He said: “I have to say the section on reform was not impressive.
“So, I think that’s an issue we will be taking forward with the government as we progress.”
The MSP also said he wanted more detail from the government on preventative spending – such as reducing health problems in society to avoid pressure on the NHS.
He objected to the government’s promise to update MSPs “in due course”, saying these are “three words I loathe”.
Mr Boyle said he shared scepticism on the issue but noted that some preventative spending is taking place.
He also called for more clarity on the government’s capital spending, saying the lack of capital pipeline plans are “barriers to supporting effective choices for parliament”.
Meanwhile, Labour MSP Michael Marra said several warnings on public finances have been issued, but it feels “like you’re banging your head against a brick wall in this”.
Mr Boyle said the government recognises the need for reform but added that progress is now needed, saying “we’ve been making these points for a number of years now”.
Public finance minister Ivan McKee said: “The Scottish Government has made improving public services a key priority, alongside eradicating child poverty, building prosperity and protecting the planet.
“We’re committed to working with Parliament on this and will continue to keep Parliament updated in the coming months.
“We have a range of programmes that are saving money from corporate expenditure that we can use to improve services.
“Examples include our Single Scottish Estate, National Collaborative Procurement, Commercial Value for Money and Digital programmes, which are securing significant cost avoidance and cash-releasing savings, expected to reach up to £280 million over a two-year period by the end of 2024-25, with further projected savings of nearly £300 million over the following two financial years to the end of 2026-27.”