New figures show the total number of Scottish postgraduate students studying north of the Border declined by nearly 2% in 2011/12 from 9570 to 9395.
At the same time, the number of postgraduates from the rest of the UK rose by more than 2% and those from overseas increased from 11,395 to 13,125, a rise of 15%.
Last year, a leading university figure warned the nation's economic future depended on an expansion in the number of Scottish postgraduate students.
Professor Sir Timothy O'Shea, principal of Edinburgh University, said creating a larger pool of more skilled workers was vital to allow Scotland to compete globally. His call followed the publication of a major independent inquiry into postgraduate education across the UK which also called for urgent reform.
The inquiry by the Higher Education Commission warned the postgraduate system excluded poorer students and failed to produce sufficient numbers of highly trained workers. Unless action is taken, the report warned UK firms will need to recruit foreign workers, or move their offices overseas, at huge cost to the economy.
The Scottish Government has already recognised the issue and £10.6 million from existing budgets has been allocated to expand provision in 2013/14.
However, student leaders and business chiefs urged ministers to take further action.
Robin Parker, president of NUS Scotland, said it was clear Scotland needed to be doing more to improve access to postgraduate education. "Currently, many postgraduate students must take on large amounts of commercial debt to gain the skills employers say graduates need to possess," he said. "In an increasingly competitive global jobs market, we need to ensure those wishing to take on postgraduate study have sufficient financial support to do so."
David Lonsdale, senior policy executive with CBI Scotland, said it was essential to have the right mix of skills to ensure Scottish business won a larger share of the global market. "The major occupational groups expected to expand in the coming years are managers, professionals and associate professionals and technical occupations, all of which need high levels of education and skill development," he said.
David Lott, deputy director of Universities Scotland, which represents university principals, added: "The 1.8% drop in Scots achieving postgraduate qualifications shows the need for expanded capacity and support for postgraduate education in Scotland, equipping more individuals for success in the modern labour market.
l Aberdeen University students have attacked moves to close down a specialist unit that helps widen access to students from deprived backgrounds.
The Students' Association condemned the decision to close the Centre for Lifelong Learning as "absolutely wrong". The attack came after the university's management published an internal review suggesting the centre could be closed with services moved elsewhere.
However, a university spokeswoman said it was "fully and enthusiastically" committed to widening access."We have not made any decisions to close – or indeed to expand – our Centre for Lifelong Learning," she said.