"There are many people who are very good at getting qualifications and passing interviews but who don't necessarily prove in the end to be much good as leaders or have very good interpersonal skills," David Alcock, of Castlehill primary, Bearsden, said.
Viv Casteel, national development officer for the Scottish Qualification for Headship, had been invited to brief the Scottish School Board Association, whose members play a key role in selecting heads. But some were less than impressed.
Mr Alcock expressed "major reservations" and said that an ability to "pass through hoops" on a training course did not make for leadership in a school.
"This is very difficult to evaluate and there is a danger that we might leap simplistically into thinking the SQH is going to be a panacea, which it may not be."
Ms Casteel said that the initiative did not stipulate particular patterns of training and there was flexibility for education authorities.
Mr Alcock also suggested that if the SQH became mandatory for would-be heads it might deter applicants committed to their area or their school "if they didn't see themselves as careerists".
The amount of time trainees might spend out of school also emerged as a concern. Mary Brindley, Inverness Royal Academy, feared that despite overall benefits some schools might suffer as individuals pursued their own career moves.
Scott Carmichael, the Scottish Office official in charge of the programme, said he understood these concerns and support would be available to meet them.
Marie Wilson, Gryffe High, Renfrewshire, pointed to the difficulties schools already experienced in finding supply teachers. "There could be problems with cover if a major part of the training programme is undertaken in school time," she said.
Ms Casteel said that local authorities were taking steps to minimise disruption.
Outnumbered ten to two
* There are only two heads on the 12-strong national advisory committee for the qualification in headship, it has emerged. They are Tony Finn, of St Andrew's High in Kirkcaldy, and Patricia Lockhart, of Kingussie High.
Matt MacIver, depute registrar of the General Teaching Council, was until recently head of the Royal High in Edinburgh. There are also two directors of education, Ken Corsar of Glasgow and John Christie of Scottish Borders.
The others are Professor Sally Brown of Stirling University, Professor Douglas Pitt of Strathclyde Business School, David Hutchison, president of the school board association, Norman Sharp, head of the Quality Assurance Agency for Higher Education, David Dimmock of Standard Life, Alex Blackwood, chief executive of the Glasgow Education Business Partnership, and Eddie Clark of the Scottish Qualifications Authority.