Fewer applying for head teacher jobs 'due to pressure'
Heavy workloads and pressure on head teachers mean fewer people are inclined to take up the job, a union has said.
More support is need to overcome recruitment issues, the National Association of Head Teachers (NAHT) Cymru said.
More than 100 schools across Wales are currently without a permanent head teacher, research by BBC Wales' Newyddion 9 programme found.
The Welsh government said there was no such "recruitment crisis in Wales".
Eighteen of the 22 Welsh councils responded to requests for information, saying they were carrying 105 head teacher vacancies within the 1,273 maintained schools in their areas.
Julian Jones, of NAHT Cymru, said the pressure on head teachers was dissuading younger teachers from applying.
"Having been within that environment and seeing first-hand what a head teacher has to cope with on a daily basis, these young people think: 'Do I want to be like that?'
"And, quite simply, the answer is 'no' and you can't blame them; and the answer will be 'no' until something changes."
Case study: 'Serious situation'
Ysgol Gynradd Llannon, in Ceredigion, has been without a permanent head teacher since the start of the academic year.
The school has had to advertise the post for a third time after receiving no applications to the first two advertisements, with a retired head teacher filling the void on an interim basis.
Lodwick Lloyd, chair of governors, said: "It's a serious situation as far as we're concerned. We need a head teacher, we need somebody here quick. Any school without a head is like a ship without a captain."
"I would level the blame firmly at the Welsh government and any government. They're the ones that have the knee-jerk reaction," Mr Jones added.
Cardiff, Newport, Neath Port Talbot and Anglesey either failed to provide information or clarify their responses.
Conwy had the highest percentage of posts unfilled at 23.8%, while Swansea had the lowest at 2.1%
Regulator, the Education Workforce Council, said more teachers were gaining the necessary qualification to be a head teacher, meaning the pool of potential candidates would increase over time.
A Welsh government spokesman said: "There is no head teacher recruitment 'crisis' in Wales".
"There are around 800 registered practitioners holding the National Professional Qualification for Headship and an increased number of candidates are undertaking the qualification this year.
"We do, however, recognise that shortages are experienced in some areas with vacancies due to local school reorganisation that is pending or underway."
The spokesman said it was "undoubtedly a challenging time" for the education system.
However, he added, it was important to remember the move towards a new curriculum had come out of the Prof Graham Donaldson's Successful Futures report, towards which the profession had contributed.