A new £4500 annual loan will be made available for all students from 2013 to help them pay for the cost of their studies, regardless of income.
The move means hundreds of students from middle-class families who previously had restricted access to student loans will be able to borrow up to £18,000 over the course of a four-year degree.
Students will pay back the money once they graduate and their annual earnings are more than £15,795.
The Government has also introduced a new minimum income guarantee for the poorest students of £7250 a year.
The change means students from the lowest-income families will get less money in grants, but their overall income will increase because of greater access to loans.
The SNP has also provided a grant to pay for the tuition fees of part-time students earning an annual income of less than £25,000.
John Field, professor of lifelong learning at Stirling University, said the changes marked another significant difference between the administrations at Westminster and Holyrood. "These are more clear signals about the policy intentions of the two governments, which are moving rapidly apart despite the similarities of many of the institutions," he said.
"The question for the UK Government is whether tuition fees will drive down participation, with a resulting impact on some universities and some courses.
"In Scotland, we have to ask whether current levels of public funding are sustainable in the long term and whether we should be investing more in vocational training."
Last night, student leaders and lecturers welcomed the additional support for Scottish students, who already benefit from free tuition fees, unlike south of the Border.
Robin Parker, president of NUS Scotland, said: "In the short-term, getting the most amount of money into students' pockets is the most important thing, ensuring people have enough money to get by and successfully complete their studies.
"While we accept bursaries will decline a little, this is more than outweighed by increases in the total amount of money available and, overall, these announcements represent the best student support package in the UK."
Lecturers' unions also welcomed the changes, with UCU Scottish official Mary Senior describing the announcement as a "real shot in the arm".
Michael Russell, the Education Secretary, highlighted the growing gulf between Scotland and the rest of the UK on higher education policy.
"Scotland is the only country in the UK with free higher education. It is the only country to see an increase in the number of young people applying for courses, as well as the highest number of students ever accepted into our universities," he said.
"Improved availability of loans and equal support for part-time students alongside free tuition will help ensure all those with potential can go to university."
However, Hugh Henry, education spokesman for the Scottish Labour Party, said the commitment fell short of the SNP's 2007 manifesto pledges to replace student loans with grants.
"There is still much more that needs to be done to ensure that students from the lowest-income households are able to reach their full potential," he said.
John Henderson, chief executive of Scotland's Colleges, called for more support for college students not entering higher education. He said: "We would welcome additional support for students on further education courses in Scotland because anyone who wishes to improve their prospects through studying should not be impeded."
Students from Scotland already get free university tuition if they study here, in stark contrast to those from the rest of the UK, who now pay fees of up to £9000 a year.
However, student hardship is still seen as a significant issue, with the rising cost of living forcing many students to work long hours during term time – or take out commercial loans.
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