And the country's economic recovery will be hampered unless providers take steps to open up the lines of credit.
The warning has come in a joint report by the Confederation of British Industry (CBI) and accountancy firm BDO in Scotland, which calls on the Government and the private sector to back the global aspirations of MSBs.
CBI research has concluded MSBs could be worth £20 billion more to the UK economy if they begin to export successfully.
The report calls for UK Export Finance (UKEF), the government department which provides exporters with credit insurance, to directly support 250 small and medium-sized businesses by 2015, having supported 52 in the last year.
In spite of more than three-quarters (78%) of MSBs expecting to generate more sales from investment abroad in the next three years, it found owners know little about Government schemes to boost exports.
Two-thirds had not heard of UKEF, while 69% did not know about UK Trade and Investment, the Government department that helps businesses expand abroad.
Martin Gill, head of BDO in Scotland, said: "Local MSBs need help to understand their potential for international success. They need hands on support to help map out the international journey and, importantly, must have access to the right advice and funding to implement their plans.
"Doing business in international markets is no longer just the realm of the region's biggest businesses but their experience and knowledge is key.
"The non-exporter of today can be the global businesses of tomorrow, but only if the Government, big business and finance providers play ball."
Meanwhile, a separate report by Close Brothers has found a quarter of Scottish firms are missing out on online sales by shying away from e-commerce.
Its quarterly Business Barometer found that, while the majority of respondents in Scotland are aware of the potential of the internet to boost trade, only 13% conduct more than half of their business online.