Public sector bodies, such as councils and the health service, spent more than £9 billion on goods and services in 2010-11. When spending on social housing and other investment in infrastructure is included, the total could be nearer £11bn a year.
Now Holyrood ministers propose legislation they say aims to ensure such spending offers the maximum benefit for the country's economy.
A consultation on the Procurement Reform Bill explores the possibility of substantially increasing the use of community benefit clauses in larger-value contracts. This could mean more contracts requiring firms to provide training, apprenticeships or other opportunities for disabled people and those who are long-term unemployed.
Infrastructure and Capital Investment Secretary Alex Neil said: "Over £9bn is spent each year through public sector contracts and this bill will mean that money works as hard as it can for our economy.
"That will include producing more training opportunities, for example through making apprenticeships an integral part of major public contracts."
According to the Scottish Government, almost half the money spent by the public sector in Scotland goes to small or medium-sized firms. Of the contracts awarded through the national portal, Public Contracts Scotland, about 75% went to businesses registered from a Scottish address.
The bill aims to ensure all public bodies use transparent, streamlined and standardised procurement procedures.
In the consultation document, the Government said it proposes a new general duty on public bodies to "conduct procurement in an effective and proportionate manner".
The bill could also make it a requirement that public bodies use a single online portal to advertise and award all contracts above a certain value threshold, thereby ensuring a "one-stop shop for suppliers seeking to do business with the Scottish public sector".
Liz Cameron, chief executive of Scottish Chambers of Commerce, said her organisation has been "pressing the Scottish Government for some time to take action to ensure public bodies adhere to best practice in procurement".
Businesses and Government have "worked in partnership to successfully deliver significant reforms, but there remains more to do to ensure the impact of public procurement as an economic lever is optimised", according to Ms Cameron.
Labour infrastructure spokesman Richard Baker claimed the SNP's approach to procurement "so far has seen a lack of focus on community benefit and tendering processes which fail to create a level playing field for Scottish firms".
He said: "This was evident in the debacle of the Forth replacement crossing contracts, which saw massive steel contracts go overseas rather than the work being carried out by companies here in Scotland.
"The SNP must learn from their mistakes on procurement and that is why this consultation is so vital for Scottish businesses and workers. We urgently need to establish a new approach to procurement as we continue to languish in economic recession and stagnation. It is time for the Scottish Government to listen to the concerns of businesses, trade unions and industry experts."
Liberal Democrat leader Willie Rennie also criticised the Government. "The SNP have failed small and medium-sized businesses with their procurement strategy since they came to power," he said.
"They may have convinced themselves they have saved money for the public purse but the reality is hundreds of small and medium-sized Scottish businesses have been denied public contracts which have been won by big businesses employing no local people.
"The test of this procurement bill will be whether it gives those businesses a realistic chance to win contracts and whether more local people get work."