Head teachers now need a new qualification before they can apply

A total of 20 of 56 unfilled posts have been readvertised, with the greatest shortage in Welsh-language schools.

The National Association of Head Teachers (NAHT) says applicants are put off by pressure, the workload and the need to have a new qualification.

But the assembly government denied a shortage, with vacancies less than 3%.

The survey for BBC Radio Cymru found nine local authorities said they had a problem recruiting a head teacher.

Thirteen councils said they had a particular problem in Welsh-language schools.

Flintshire has the greatest number of head teacher vacancies, with eight jobs to be filled, followed by Cardiff and Anglesey with five empty posts each.

Around 1,000 head teachers will retire in Wales within 10 years

Five local authorities, Neath-Port Talbot, Newport, Powys, Swansea and Carmarthen, each have four schools with no appointed head teacher.

Merthyr Tydfil has three posts to fill, while Blaenau Gwent, Rhondda Cynon Taf, Pembrokeshire, Wrexham and Ceredigion each have two vacancies.

Four other authorities reported a single vacant head teacher post.

'Voting with feet'

Many of those questioned blamed the introduction of a new qualification would-be head teachers must have before they can apply for a head teacher post.

Iwan Guy, acting director of NAHT Wales, said Wales would have to replace more than 600 retiring head teachers in the next five years.

"I think the workload has been the final straw. There's been so much pressure put on head teachers, with initiative after initiative, an overload of initiatives, and there's only so much that one can do in the day," he said.

"And head teachers are voting with their feet by leaving and the deputy head teachers are saying 'I'm not taking that job on when I see what it's doing to my head teacher'."

Pat Jones, who is retiring as the head of Ysgol Gynradd Gymraeg Castell Nedd, Neath, said initiatives to bring in new working practices mitigated against head teachers' own work-life balance.

'No shortage'

"It's a job I have enjoyed over the last 22 years but certainly the job has changed," she said.

"The administrative burden of the job has become greater and it seems as though someone somewhere has decided that the head teachers job will be an administrative role."

The assembly government denied there was a shortage.

"The BBC's figures are not out of line with predictive figures for turnover / recruitment, and represent less than 3% of the total head teacher workforce," said a spokesperson.

"Recruitment will be in process now for posts available in the new school year. In Wales we are developing a very healthy pool of qualified heads."

The assembly government said about 360 teachers were working to gain the qualification needed to apply for a head teacher post and more than 500 new heads had benefited from an early support scheme.