And cash-strapped schools face more worry after a survey by the National Association of Head Teachers Cymru showed that 18 of Wales's 22 local authorities have made cuts ranging from 1 to 3.6 per cent in education spending this year.
Opposition parties are threatening to throw out a revised pound;14.4 billion budget, laid by the minority Labour administration on Tuesday, on educational grounds.
Ieuan Wyn Jones, Plaid Cymru's leader, said the government's failure to come up with pound;17.9m to protect schools from local government efficiency savings, and a lack of extra money to bridge a historic funding gap between universities in Wales, England and Scotland, had led to the stand-off.
Despite the parties meeting five times since an initial draft budget was rejected in October, agreement has yet to be reached. Failure to do so means vital cash cannot be passed on to frontline public services, including schools, for 20078 budgets.
New money announced in Tuesday's draft budget included pound;2 million for schools' energy bills (with a restriction that local authorities should not expect more than 0.3 per cent efficiency gains from schools), and pound;6m for universities.
Sue Essex, the government's finance minister, said she could not magic up any more money.
And a government source said: "If the pound;10m earmarked in the draft budget for the foundation phase does not get through to schools soon, it will be the opposition's fault."
But as TES Cymru went to press, the politicians were hoping extra cash from Chancellor Gordon Brown's final pre-budget report would help avert a crisis. Mr Brown announced an extra pound;9m for Wales, next year, as part of an additional pound;165m over four years.
Meanwhile Anna Brychan, director of NAHT Cymru, said figures from its latest survey of local education authority spending made grim reading, and compounded fears that 1 per cent government efficiency savings have been passed directly to schools.
It also showed that some local authorities were still not allocating as much to education as recommended by the Assembly government when calculating budgets.
She said: "At a time when school leaders are attempting to introduce big curriculum changes and implement the national workload agreement - as well as a huge range of other costly challenges - these figures demonstrate the scale of difficulties facing our schools."