Since the establishment of the Welsh Assembly a "funding fog" has descended over the country, members of the Secondary Heads Association in Wales, who met at Llandrindod, Powys, were told by general secretary John Dunford.
The Assembly receives money from government and members decide how it is distributed.
There is no Welsh equivalent of the standard spending assessment, the Government's assessment of what English councils should spend on education, and there is little ring-fencing of authority funds.
SHA Wales said the money that should be spend on education is not getting through. Schools insist they did not get a penny of the pound;35 million the Government allocated for sixth-form reform.
Hywell Gruffydd, head of Chepstow comprehensive, Monmouthshire, said: "We are fobbed off all the time. The Government says the money is there, the Welsh Assembly sys it has passed it to the local authority but the authority denies any knowledge. The money goes into a black hole and we have to go looking for it."
But Jane Davidson, the education minister, told heads that the mechanism was here to stay and warned them not to push the issue.
"Decisions made in England have very little bearing on decisions made in Wales. That is the real world in which we both live. I am aware of your concerns about it but it is not going to change."
The minister did make a concession over funding for the new leadership pay rises. She agreed a one-off payment of pound;7.9m, when it was discovered that pound;3.1m allocated to local authorities, to cover the wage rises for senior staff, did not reach schools.
Each primary and secondary school will receive pound;1,000, plus pound;10 for each primary pupil and pound;15 for each secondary pupil. Nursery schools will get pound;1,000 and special schools pound;2,500. Money left after pay increases are met can be used for school improvement.
Schools will have to fund the extra costs themselves in 200102.