Headteachers' heavy workloads are out-of-control and could be unlawful, the annual conference of the National Association of Head Teachers Cymru will be told today.
Mick Brookes, its general secretary, was expected to tell delegates in Swansea that long hours and considerable teaching commitments are having a serious effect on schools. But he will also say there is a general consensus among heads that teachers are not under the same pressure because the workforce agreement is being enforced well.
The message will be that teachers are achieving a much better work-life balance than heads. It comes a week after Ed Balls, England's Schools Secretary, announced that schools found flouting the workforce laws in England and Wales will suffer punitive measures, including the loss of budgets and replacement of governing bodies.
An Assembly committee also took evidence this week from the NAHT Cymru over excessive workload. Iwan Guy, the union's acting director, told Assembly members that the majority of heads are working extensive time outside their contracted hours to fulfil the demands of their posts.
"The workforce agreement has worked for classroom teachers, but not for heads," he told TES Cymru. "We are conscious that there are many heads in Wales, particularly in small schools, who have more than a 50 per cent teaching workload - and that's against the law."
The workforce agreement, signed by the Government, unions and employers in 2003, says that teachers should have 10 per cent of their time set aside for planning preparation and assessment; they should cover for colleagues no more than 38 hours a year; and they should no longer do more than 20 administrative and clerical tasks a year.
But Mr Guy will refer to a recent NAHT Cymru survey that found almost half of its members worked between 49 and 59 hours per week during term time. Many schools do not provide dedicated headship time - which is a legal requirement - and some governing bodies were failing to enforce it, claiming a lack of resources.
Mr Guy is calling for "system-wide recognition" that contractual change covers all members of the teaching profession.
But some experts say that heads need to change their working practices. Distributive leadership is increasingly being hailed as the way to achieve a manageable workload.
The theme of this year's NAHT Cymru conference is "Challenge and Change". Karl Napieralla, head of education for Neath Port Talbot council, was expected to open the conference. The former head of Cwrt Sart School in Briton Ferry and current chair of the Association of Directors of Education in Wales was awarded an OBE earlier this year for his services to education.
As well as addresses from top NAHT Cymru officers, delegates at the conference were due to hear from two leading speakers, the author Professor Hywel Teifi Edwards, and lecturer and poet, Mererid Hopwood.
They will also be given the opportunity to quiz Jane Hutt, the education minister, who was due to take questions from the floor after addressing the conference today.