Welsh universities' plans to charge students tuition fees of up to £9,000 a year have been rejected.
Initial fee plans from universities were turned down by the body that funds higher education.
Education Minister Leighton Andrews said it showed Wales was taking a "robust" approach towards university tuition fees.
A Welsh Government subsidy means Welsh students will not have to pay the raised fees, unlike those in England.
If Welsh universities want to charge more than £4,000 in 2012/13 their fee plans must be approved by the Higher Education Funding Council for Wales (Hefcw).
Plans will only be agreed if institutions show they meet certain requirements, including on equal access and improving the student experience.
Answering questions in the Senedd on Wednesday, Mr Andrews said Hefcw wrote to all higher education institutions (HEIs) on Friday to tell them that in their present form, their fee plans did not meet the requirements.
Mr Andrews said: "In other words all HEIs in Wales have been warned that as currently presented their fee plans would be rejected.
"This demonstrates that the process we are following for fee plans in Wales is far more robust than that operating in England."
Hefcw will receive revised plans at the end of June and make a final decision on 11 July.
Mr Andrews announced last year that Welsh students will be shielded from increased tuition fees, wherever they study in the UK. Their fees, currently around £3,400, will only rise in line with inflation.
He said the government thought its estimated cost of the policy up to 2016/17 was "robust".
He added: "It is notoriously difficult, let me say, to estimate some of the issues around cross-border flow of students and we are still not certain yet of all of the fee levels at every higher education institution operating in England and Wales.
"So there are always going to be uncertainties around this, but we are confident and we have made a commitment - as a party we made a commitment in our manifesto, one of our pledges - to ensure that Welsh students would not pay higher fees wherever they study, and that is a commitment for the life of this assembly.
Aberystwyth, Cardiff, Bangor, Glamorgan and Newport universities said they wanted to charge the maximum £9,000. Some courses at Newport would cost £8,250.
A spokesperson from Hefcw said any institution which plans to charge more than £4,000 for eligible students had to submit a fee plan, detailing investments they intend to make using a proportion of this new income in order to encourage equality of opportunity and promote higher education.
"All plans must be agreed by Hefcw before the new fees can be charged," said the spokesperson.
"We have now written to all 10 higher education institutions and four further education colleges which submitted fee plans by 31 May stating that the plans in their current form do not meet the necessary requirements.
"We expect to receive revised plans, taking account of the concerns we have raised with individual institutions, by, or very soon after, the end of June."
It said it did not intend to provide detailed commentary on submissions and colleges' intentions before it made an announcement on their final acceptance or rejection on 11 July.
But the Hefcw said in many cases "the scale of expressed ambitions" needed to be increased or better demonstrated in terms of clearer targets, to they could judge whether expectations were being met.
Higher Education Wales, which represents universities, said the fee plans were ambitious proposals to widen access: "No university has ever been under the illusion that the approval of fee plans would be akin to a 'rubber stamp' - this was always going to be a challenging, iterative process".
NUS Wales president Katie Dalton said: "I hope this is not a political stunt that simply allows the minister to hit the headlines, as students cannot afford for politicians to play games with their futures.
"Instead, it needs to send a very clear message to Welsh universities that they have to take this process seriously."
Conservative Angela Burns said: "The minister has put Welsh universities in the impossible situation of either charging the maximum fee or risking severe underfunding compared to universities in England, which can charge higher fees."
Plaid Cymru's Simon Thomas said: "If such large sums are charged there is a serious risk that a university education will be out of reach for many."
He said the Welsh Government's policy was based on universities charging an average £7,000.
In England, universities have been given permission to charge up to £9,000 per year.
This will be paid up-front to the university as a government loan, which students then repay after they graduate, once their their yearly income reaches £21,000.
English universities wanting to charge more than £6,000 have been required to submit "access agreements" to the Office of Fair Access (Offa), detailing the measures they will take to attract students from disadvantaged backgrounds.
Offa is currently assessing them and is due to publish the approved agreements by 11 July.
The University and College Union (UCU) said news that Welsh universities have had their initial plans for tuition fee rises rejected was worrying news for English institutions.
The union said that the news will only "add to the mess that is the government's failing fees policy".
The National Union of Students (NUS) said Offa must follow Hefcw's example and ensure higher fees in England do not damage access.
"The decision to raise the tuition fee cap will put many students off applying for university and if Offa lacks the powers it needs, ministers must intervene to ensure that no ambitious qualified student is prevented from going to the university of their choice for financial reasons," said Aaron Porter, NUS president.
Scottish students, however, are not required to pay any tuition fees.