Shadow business secretary John Denham has accused the coalition of "railroading" through its plans to raise university tuition fees.
He said the government had not given enough detail on several issues, such as access for poorer students.
It came as the students union said the government plan was based on a "dodgy dossier" after think thank IFS retracted its analysis of the plan.
The IFS said it was not deliberately misled but had used wrong assumptions.
A vote is widely expected to take place before Christmas on allowing universities to raise tuition fees to up to £9,000.
Mr Denham said it would be "wrong" to ask Parliament to vote to raise the fee cap until more the details of the government's plans have been published on a series of issues which he outlined:
- The details of the access agreements, under which universities will have to commit to help recruit students from disadvantaged backgrounds if they are to charge the highest level of tuition fees
- What is meant by the government's stipulation that universities will only be allowed to charge £9,000 in "exceptional circumstances"
- What provision there will be to help equip and recruit students from poorer backgrounds given that the future of the existing body, Aimhigher, is in doubt
- Whether and how the government plans to limit student numbers
- The government's plans to allow private institutions to offer degrees
- Plans for a National Scholarship Scheme
- The estimated cost to the taxpayer of its plans, given that independent analysts have said the government has been over-optimistic in its assumptions
Mr Denham said that before MPs were asked to vote they should be able to see the government's planned white paper on higher education, which is expected in early 2011.
"Anything short of this will be seen as a clear attempt to railroad the policy change through without proper public scrutiny," he said.
A spokeswoman for Business Secretary Vince Cable said the government had clearly set out reforms that will "mean graduates' payments are fairer and more progressive than the system Labour left behind".
She said there was "no question" of denying Parliament a chance to examine and debate all the reforms, and both houses would have the chance to debate the changes before any votes.
"Parliament will also have the chance to discuss the White Paper once it is published and we will listen carefully," she said.
"It would suit the Labour party to delay any debate in parliament so they can avoid any scrutiny of their own policy which is hopelessly confused, but the government wants to make progress on our reforms to give certainty to young people thinking of applying to university," she added.
Meanwhile, on Wednesday, the Institute for Fiscal Studies, a respected economic think tank, retracted its analysis of the government's proposals.
It had concluded that the richest half of graduates would be better off under the government's plan, compared to under proposals from the independent review chaired by Lord Browne.
The IFS said it had assumed the £21,000 earning threshold at which students will have to start paying the funds back was according to 2012 prices, whereas in fact it was based on expected prices in 2016.
This means that the threshold will be equivalent to £18,500 in today's money, according to the Million+ group of universities.
The error came to light after the publication Research Fortnight revealed an email from Lorraine Dearden of the IFS.
It quoted her as saying the IFS "has now found out that key parameters of what the government is proposing have changed but this has not been made clear in any of their papers".
It was unclear exactly what was meant by "have changed".
The IFS later said it had "not been deliberately misled" by the government, and that Lord Browne's review had apparently also assumed the threshold was in 2016 prices.
But critics of the government's plans said it raised further concerns.
Aaron Porter, president of the National Union of Students, said "plans to rush through a tripling of tuition fees are based on a dodgy dossier".
"The numbers do not add up and ministers' claims that their policy will be fair for students or good for taxpayers lie in tatters," he said.
An analysis by the Higher Education Policy Institute last week said the cost to the public purse of the government's plan would be "much higher than expected".
It said the government had estimated graduate earnings too high, and assumed too few universities would charge the highest level of fees.
Pam Tatlow, chief executive of the Million+ group, which represents new universities, said the coalition's modelling and ministers' claim that their proposed system is progressive were "inaccurate and misleading".
"Ministers need to go back to the drawing board and remodel the implications of their proposals for students, graduates and the taxpayer before they ask MPs to vote for any amendments to the present system and before they ask universities to take another hit in teaching funding," the group said in a statement.
A spokesman for the Department of Business, Innovation and Skills said: "Our student and university finance reforms are fairer and more progressive than the present system, protecting those from low income backgrounds going to university and those who work in low income employment post-university and the IFS analysis supports this view."
Research published on Thursday by the Higher Education Careers Services Unit showed that nearly eight in 10 final-year students (78.2%) worked, with 42.8% of these working during holidays and term time.
Of those who worked in term-time, 84% said they worked to meet essential living costs, while 62% said they wanted to avoid debt.
Students have been angered by plans to raise fees, particularly as they are supported by the Liberal Democrats, who pledged to oppose any hike in degree charges.