Around half of the additional 30,000 roles added to the overall tally of public sector jobs since the start of the pandemic have been within health.
Ms Forbes confirmed she expects other parts of the civil service to feel more pain to protect these jobs.
The SNP MSP refused, however, to set a figure on how many overall jobs she expected to be lost in the SNP’s latest round of civil service cuts.
Areas most likely to see job cuts will be those with significant additional staff hired to tackle the impact of the pandemic.
Ms Forbes said she would discuss the issue of workforce numbers and public sector with unions – a pledge that comes amid threats of widespread industrial action and as ScotRail battles the train drivers union Aslef over pay.
Instead public bodies will be expected to use “effective vacancy and recruitment management”, the redeployment of staff, and a reduction in duplication to find savings, she said.
The finance secretary has also committed to a freeze in the overall public pay bill, a move that necessitates a cut in overall staffing numbers.
Asked whether the NHS and the wider health sector would see cuts, Ms Forbes said it was “unlikely” to be the case as some parts of the public sector would “need to grow to an extent further”, referencing the National Care Service.
She said: “There will be other parts of the public sector which no longer need to maintain the Covid expansion of workforce.
"Rather than taking a UK Government approach, which is to put arbitrary figures on, I think their figure was 91,000 FTE, which was to bring their staff numbers down to 2016 levels, we have set out that we will freeze the pay bill, which does not equate to a freezing of pay levels.
"But we want to work with employers and trade unions over the next few months, certainly in advance of the Budget, to understand how we can manage those workforce numbers in a flexible way which allows some parts of the public sector like the health service to continue to grow where it needs to grow, and other areas to decrease where they don’t need that post-Brext, post-pandemic levels of staffing.”
Ms Forbes also highlighted the area of business support and grants services, such as those offered by Enterprise Scotland, as a potential location for reducing duplication.
However, she confirmed she did not see any of the Government’s enterprise businesses becoming victims of the likely shrinking of the public sector.
The SNP politician was pressed on whether some parts of the public sector would see tougher cuts, with Labour finance spokesperson Daniel Johnson asking her whether she expected 8,000 jobs to be lost in the civil service.
Ms Forbes said it “is a statement of fact” to say areas that are not highlighted as needing to return to pre-Covid levels would have to go “further” in their cost-cutting efforts.
"You can do that through effective vacancy and recruitment management, you can do that through redeploying staff,” she said.