The government has announced a £180m bursary scheme to replace the Education Maintenance Allowances which were scrapped in England last year.
The £560m EMA scheme had provided up to £30 a week to help low-income students stay on at sixth forms and colleges.
Education Secretary Michael Gove said the revised system would provide a "more targeted" support system.
Labour's Andy Burnham attacked the plans as an attempt to "put a positive gloss" on deep spending cuts.
The shadow education secretary told MPs that Mr Gove had "taken a successful policy, which improved participation, attendance and achievement in post-16 education, and turned it into a total shambles".
Mr Burnham said the re-launched support scheme represented a "humiliating climbdown".
But Mr Gove said that MPs had to consider "whether it is socially just to be paying 45% of students a cash incentive to stay in learning when we could be concentrating our resources on removing barriers to learning faced by the poorest".
The UCU lecturers' union said the reduction in overall support raised "the prospect of thousands of poorer students being priced out of studying".
The replacement student support scheme is intended to target funding at those most in need.
The biggest amounts - £1,200 per year - will be given to 12,000 teenagers with the greatest needs, such as pupils in care, care leavers and the severely disabled.
After these payments, from the £180m overall funding, there will be £165m for colleges and schools to make discretionary payments to support low-income students with costs such as transport, food and books.
The Association of Colleges highlighted the importance of being able to help students with transport costs, which had been a "key barrier".
There will also be a partial reprieve for students who are already on courses and receiving EMAs, who had previously not known whether funding would continue beyond September 2011.
Those who started courses in 2009-10 will now continue to receive the same payments until the end of the 2011-12 academic year.
And students who started courses last September and currently qualify for £30 per week payments will receive continuing support of £20 per week until the end of the next academic year.
Mr Gove said that the bursary scheme would "ensure that every child eligible for free school meals who chooses to stay on could be paid £800 per year - more than many receive under the current EMA arrangements".
Under the EMA scheme, 650,000 16 to 19 year olds young people from low-income families had received grants of between £10 and £30 per week.
The allowances had been introduced by Labour in an attempt to tackle the long-standing problem of a high teenage drop-out rate from education, particularly among poorer students.
But the coalition government attacked the EMA scheme as wasteful - and announced last year that it would replace it with a smaller, discretionary fund.
Leader of the ASCL head teachers' union, Brian Lightman, said schools and colleges would be "relieved that the government has listened to their concerns about the abolition of the EMA and the harmful effect it would certainly have on efforts to improve social mobility".
But Mr Lightman said the replacement system had to be explained as soon as possible to young people, so doubts over funding would not damage efforts to encourage them to stay in education.
The National Union of Students said that the overall package represented a "shadow of its predecessor".
"Almost £400m is still being cut from support to young people and EMA, which has been proven to work by ever measure available, is still being scrapped," said NUS vice-president, Shane Chowen.
James Mills of the Save EMA campaign said: "If Michael Gove thinks that he deserves credit after giving 70p extra a week to 12,000 of the poorest students whilst at the same time taking away £30 a week to many of their classmates whose finances are marginally better, then he really is delusional."
EMA schemes in Scotland and Wales are continuing - and the allowances in Northern Ireland are under review.