The Government remained embroiled in a row over public sector pensions tonight after failing to win the endorsement of its final offer from the country's biggest teaching unions.

The executive of the NASUWT refused to sign up to the offer, saying it reserved the union's position and claiming that the Department for Education's (DfE) process of trying to reach a deal had been "completely unsatisfactory".

Meanwhile, the executive of the National Union of Teachers called for further "urgent discussions" with the Government on the future of teachers' pensions.

The moves followed a decision by Unite's health executive yesterday to reject the proposed deal for NHS workers, and a decision by the British Medical Association to survey around 130,000 doctors and medical students on the Government's final offer, raising the prospect of their first industrial action ballot for over 30 years.

Chris Keates, general secretary of the NASUWT, said: "Put bluntly, the NASUWT national executive has recognised that the process the DfE used to seek to reach agreement by its imposed deadline of December 20 was a debacle.

"Valuable time was wasted by the DfE. It failed to provide the necessary information on which meaningful discussions could take place, chopped and changed its mind on the issues which were up for discussion, and presented some potential changes which did not have Treasury approval."

Ms Keates claimed teaching unions were "pressurised and threatened" to sign up to a document last month when a final draft was not available.

"Even when a document was produced as the final meeting was breaking up, overnight the wording was changed unilaterally by the DfE.

"In these circumstances, it would have been completely irresponsible for the NASUWT to have signed up to the heads of agreement.

"These are critical issues which have profound implications for teachers, for the profession and for the education service.

"The Secretary of State promised that he would ensure that the interests of teachers were protected and that he would devote all the time and resources necessary to ensure that every effort was made to reach an agreement.

"I will therefore be writing to the Secretary of State today requesting that he meets as a matter of urgency with the NASUWT and the other unions which have reserved their position on signing the heads of agreement to discuss fully these concerns."

The NUT said it remained concerned about proposed increases in employee contributions and pension ages, adding that increasing contributions at a time of real terms pay cuts will lead many teachers to opt out from pension provision.

General secretary Christine Blower said: "We remain committed to a negotiated agreement on pensions but these proposals will not, in our opinion, serve the interests of teachers or the education system.

"Michael Gove assured us in December that sufficient time and resources would be provided to secure a solution. The Government must face the fact that further discussions and additional funding are needed."

A Department for Education spokesman said: "The deal we set out before Christmas is a fair one for teachers and affordable for taxpayers. It means that teachers will still get a far better pension than the vast majority of people in this country - while we can keep long-term costs firmly under control.

"It's disappointing the NUT and NASUWT restated their position on last month's deal. We've already addressed many of teachers' concerns, particularly around early retirement. We are now ready to have detailed, technical discussions to reach a final settlement - but have made clear that the broad deal on the table is as good as it gets. Other unions have given a far more positive response and will be consulting with their executives later this month.

"Reforms to public sector pensions are essential - the status quo has never been an option. The cost to the taxpayer of teacher pensions is already forecast to double from £5 billion in 2006 to £10 billion in 2016 and will carry on rising rapidly as life expectancy continues to improve."

Dr Mary Bousted, general secretary of the Association of Teachers and Lecturers, said the offer will be put to its members ahead of a meeting of the executive committee on January 28.

"The government was quite clear that the offer was a final offer, and that any further industrial action would not improve it.

"In the current economic and political climate we believe that the offer is the best deal we could get through negotiation. Further prolonged industrial action, which is the only alternative, could lead to the government imposing significantly worse terms than are currently offered."

GMB civil service representatives today agreed to proceed with negotiating a final proposal that can be put to members.