Headteacher Dyfrig Ellis came up with the idea after meeting representatives of a Dutch company, Nedap Education, while attending an information and technology conference in London.
"In Holland, some pupils wear a type of electronic bracelet allowing them access to various rooms at the school while denying them access to others," he said.
"I asked Nedap whether this could be developed to raise an alarm if a child left the premises, in much the same way as an alarm in Debenham's would sound if you left the store without paying for your clothes.
"This is not a kneejerk reaction. We have never lost a child at lunchtime and we are not looking at tracking or monitoring children. This is simply a tool we might use to keep children safe."
Mr Ellis, 37, who eight years ago became the youngest headteacher in Wales when he took charge of Y Tyle'r Ynn primary at Briton Ferry, condemned some of the "sensationalist" reporting on his proposals.
"I received one letter suggesting that our idea indicated the arrival of the police state," he said. "But I have not received a single complaint from any of the 400 parents whose children attend our school.
"Five years ago, when I began locking external doors, people were saying we were locking children in. Today I think there would be far more complaints if certain doors were not locked. The world has moved on.
"Bluetooth (a standard developed by a group of electronics manufacturers that allows any sort of electronic equipment to communicate without wires or cables) is a wonderful facility, and we are looking to embrace this new technology.
"For example, I have asked Nedap to look into whether children wearing these bracelets could be automatically registered on arrival at school."
Mr Ellis, together with staff and school governors, intends to meet with Nedap representatives for talks next month.
Christine Morgan, Nedap's UK manager, said the use of cards to control access to secondary schools and universities was widespread in the Netherlands.
"While our market is secondary and higher education, we are considering this request," she said.
"We are not tagging children, we are trying to monitor attendance. The device they may wear has to be selected with that age group in mind, but a removable type of watch-strap could be considered. Parents would have the right to object if they wanted to."
Ms Morgan added that she favoured the concept of a remote alarm which would activate a teacher's mobile phone if a child strayed from the school campus.
"I don't like the thought of a loud alarm going off and scaring children half to death," she said.