The Education Secretary Alan Johnson is urging more universities to get involved with the development of new work-based Diplomas for England.
The Diplomas will come in from 2008 in England
Ministers want universities and employers to help design and deliver the Diplomas for 14 to 19-year-olds.
But head teachers warn that unless universities recognise the Diplomas, they will be seen as second-best.
Leading universities in the Russell Group say they already accept students with a wide range of qualifications.
The Diplomas are being introduced from 2008 to bridge the gap between vocational and academic routes.
Mr Johnson told a higher education conference the changes amounted to "the most radical educational reforms happening anywhere in the world".
"If every child is to reach their full potential in life, we need a rich curriculum which speaks to the talents and abilities of every child," he said.
"Getting involved in diplomas isn't an optional extra, it's a necessity: essential to shaping the future direction of education in this country.
"We need you all to be following the lead that has been set by institutions like Salford who have been instrumental in developing the construction diploma.
"Likewise, Warwick and Northumbria have been helping to steer the direction of the IT diploma."
Universities are seen as crucial to the success of the Diplomas, which will initially cover five areas of work: construction, engineering, health, IT and media.
Students will also be expected to pass tests in maths, English and IT. Highest-level students will have to do an extended essay.
There will be three levels of Diploma, rising to level 3, which the government says is equivalent to three A-levels.
Ministers say the qualification will be accepted by universities and colleges, as well as allowing students to go directly into work if appropriate.
Head teachers are warning that unless universities recognise the Diplomas for entry to all courses, the qualification will be seen as second class.
John Dunford, the general secretary of the Association of School and College Leaders (ASCL) told the BBC News Website: "It is vital that universities accept Diplomas as an entry qualification to their high-demand courses.
"It is not enough for universities to accept them only if someone was doing engineering for example."
The association believes it would be easier if the Diplomas were given clear parity with A-levels.
University leaders say they are pleased to be involved with the new qualifications.
A spokesperson for Universities UK - the body representing university vice-chancellors - said: "Universities UK is pleased that the higher education sector has been asked to be involved in the design of the 14-19 vocational routes.
"Universities UK has always maintained that vocational pathways need strengthening in order to encourage more young people to stay in learning."
Dr Wendy Piatt, director general of the Russell Group of leading universities said: "Russell Group universities are committed to opening their doors to candidates with the ability and potential to flourish on their chosen course.
"Our universities consider students with a wide range of qualifications.
"We recognise the importance placed on the development of the 14 to 19 Diplomas and we are working enthusiastically with the DfES to help shape them."
Earlier, Mr Johnson denied that Diplomas would lead to an exams hierarchy.
He told MPs on the Commons Education and Skills Committee that the changes were going "horribly right".
Mr Johnson made headlines last month by saying the introduction of the Diplomas could go "horribly wrong", but later said the remarks were made in the context of the complexity of the introduction of the qualifications.
MPs told him parents and students were confused by the various paths and qualifications they could take.
The first five Diplomas are due to start next year, in 145 pilot areas involving some 40,000 young people.
By 2013, there will be 14 Diplomas in different employment-related areas.
Mr Johnson told MPs that two-thirds of local authorities were now involved in developing and providing the qualifications.