Falling rolls could be giving councils across Wales a "convenient opportunity" to make money from school closures. One source told TES Cymru school land sales could "generate lots of cash".
Overall, Wales has 78,380 surplus places (14.7 per cent), which could rise to more than 100,000 by 2013 if no action is taken, according to the Assembly government.
In Swansea, around 1,000 places will become surplus over the next few years. Last week the council shelved plans to close Dylan Thomas community school and merge it with Bishop Gore secondary. Other proposals include closing one primary and a nursery school. The council has pledged to re-invest any money raised from closures back into education during the first phase of its reorganisation plan.
Councillor Mike Day, Cabinet member for education, hopes any gains from future reorganisation will also be re-invested in education, but said there were no guarantees. The council's policy - introduced under the previous Labour administration - is for receipts to be held centrally.
Gethin Lewis, of the National Union of Teachers Cymru, said: "If they are going to close schools then that money should be recycled within the education budget. The NUT is aware that local education authorities are under pressure to make 1 per cent savings every year. But if schools close it should be because of educational priorities, not financial ones."
The Assembly says it is encouraging LEAs to rationalise provision, and where this involves school closures to consider selling the land and re-investing the capital receipt in new school buildings. But closure programmes can also be a headache for officials. Just one objection lodged against a plan means it has to be sent to the education and lifelong learning minister's office for a decision.