New legislation will give teachers "unprecedented" powers to search pupils that will exceed those of the police.
The Coalition's Education Bill, published last week, will dramatically extend teachers' search powers, which human rights group Liberty has described as being "proportionate to terrorism investigations".
The bill gives teachers the power to seize any electronic device - including mobile phones - and examine all data they may contain.
It also allows teachers to erase any files or data, if a member of staff believes it is reasonable to do so.
Announcing the bill last week, education secretary Michael Gove said the legislation signalled that the Coalition was "absolutely on the side of teachers", and it would free staff to "impose the penalties they need to keep order".
But experts have claimed the new powers could lead to confrontations between pupils and teachers.
Ben Bowling, director of criminological studies at King's College London, described the new policy as an "extraordinary extension of powers" that go "beyond those of the police".
"This is an extraordinary extension of policing powers through teachers, which has the potential to lead to undue intrusion into privacy as well as confrontations between school children and their teachers," Professor Bowling said.
"One can only hope that teachers use their common sense and refuse to be turned into police officers."
But Brian Lightman, general secretary of heads union the Association of School and College Leaders (ASCL), said he "welcomed" the power to search mobiles becoming law.
"We are very pleased that ASCL's request for the power to request for the power to search mobile phones has been included in the bill. Searching mobile phones will help schools to combat cyber bullying," Mr Lightman said.
Human rights pressure group Liberty described the measures as an "excessive" intrusion into young people's lives.
Director Shami Chakrabati said: "Asking teachers to play policeman to their students risks destroying a sacred relationship of trust.
"Confiscating mobile phones and looking through the phone records, text messages and address lists is proportionate for terrorism investigations, not breaches of school rules."
Liberal Democrat peer Baroness Walmsley, who co-chairs the party's parliamentary policy committee on education, said she doubted whether the powers would even be popular with teachers.
"I don't think teachers want them, I think teachers just want to teach," she said. "The vast majority of schools don't have these problems, they just want to get on with the job. It gives me enormous concern for the rights of the child."
A DfE spokesperson said: "We simply cannot continue to foster a culture in our schools where teachers are continually undermined by a minority of pupils because they don't have the powers they need to tackle poor behaviour.
"We know that teachers back our plans, with this week's select committee report stating that the majority of professionals want greater search powers to deter bad behaviour. A recent YouGov poll also showed that eight out of ten parents support the plans."