The Association of Teachers and Lecturers (ATL) has called for a government investigation into the biological and thermal effects of "wi-fi" networks.
The union claimed wi-fi is in 70 per cent of secondary schools and 50 per cent of primaries.
However, health experts said there was no evidence the technology had any detrimental effect.
Colin Kenney, of Cookstown High School, in Northern Ireland, who called for the investigation, said that international experts had called for caution when using wi-fi technology.
He asked: "Have we the moral right to ignore the warnings – simply for access to a few more computers – and are our pupils going to thank us in the years to come if they have become sterile or suffer from cancer brought on by, or exacerbated by, exposure to wi-fi?
"Perhaps they will just be eternally grateful that we enabled them to finish their presentation for geography."
Mr Kenney demanded long-term safety studies until it could be confirmed that the technology was safe, and called for a return to wired internet access.
He added: "As teachers, we may have to wait a little longer for the new ICT (information and communication technology) suite to become available, but at least we will be safeguarding health."
However, Dr Michael Clark, scientific spokesman for the Health Protection Agency (HPA) said: "On the basis of research so far, there is no hard evidence of any ill health effects from wi-fi.
"The signals are very low, in fact there is more wattage coming from the battery."
A spokeswoman for the Scottish Government echoed the HPA's message.
She said: "Based on the advice from our principal advisors the Health Protection Agency, there is no consistent evidence to date that wi-fi adversely effects the health of the general population.
"However, with regard to the need for precautions, the Health Protection Agency is intending to carry out a research project to measure the effects of radio signals from wireless networks."
She said the results of the study would be used to inform future policy on the technology.
Concerns surrounding radiation from mobile technology have become a perennial issue.
The Professional Association of Teachers has also previously called for classroom wi-fi networks to be halted until potential dangers are known.
A BBC Panorama investigation in 2007 found that, at its peak, the radiation from a wi-fi-enabled laptop computer is three times that of a mobile-phone mast.