A survey by the Headteachers' Association of Scotland of members in 28 authorities has found growing anger at plans to thin the ranks of depute heads and principal teachers in the summer management shake-up arising from the post-McCrone agreement.
By a two to one majority, heads say they are increasingly concerned that the new structures will fail to deliver the improvement agenda.
Many believe that axing managers will simply dump more problems on their desks and say they already work up to 70 hours a week.
Mike Doig, HAS president and head of Bearsden Academy in East Dunbartonshire, described the problem as "bodies on the ground". The association is particularly critical of Argyll and Bute which aims nearly to halve the number of promoted jobs as more management posts are established in primaries.
The Educational Institute of Scotland has also warned of chaos in all 10 of the authority's secondaries if the plans go ahead.
Mr Doig said: "What we have got could be compromised if there are far fewer managers in middle and senior management. The structures do not always lend themselves to meeting the requirements of the national priorities and local improvement plans that councils have to have by law. Members are saying that they will struggle to take the improvement agenda forward and struggle to stand still."
With fewer PTs around, there could be less monitoring of teachers, and with fewer senior managers, less monitoring of departments. Secondary heads also fear discipline strategies could be at risk as principal teachers are generally the first point of contact for class teachers who want help with problem pupils.
"There is a high level of concern over any changes in management structures that would actually result in fewer promoted staff being available to deal with the increasingly challenging behaviour of pupils, both in and outside the classroom," Mr Doig insists.
He warns of less supervision in playgrounds and corridors and says that the health, welfare and safety of pupils could be at risk.
Heads are also alarmed at the imminent job-sizing exercise with suggestions that many future postholders will find their salaries downgraded by the formula deployed. It might be argued that some heads are being paid too much for what they do.
"This will do nothing for the morale of members," Mr Doig insisted.
Heads accept that some posts will vanish because of the national agreement but assert that some authorities are over-zealous.
"Several proposals are blatantly aimed at reducing the costs of promoted posts in secondary schools. The HAS does not accept that the enforced change should provide an opportunity to make cuts in the funding for secondary education, nor indeed for any sector," Mike Doig said.