Teachers are concerned over the government's plans to increase the power they have to search and discipline students.
A survey by the Association of Teachers and Lecturers (ATL) found that four in ten education professionals believe this could damage relationships with pupils.
Furthermore, almost 30 per cent of respondents said having the power to confiscate mobile phones and cigarettes could cause problems with parents and carers.
In addition, it was revealed that many members of staff are worried that allegations may arise after they search pupils.
Commenting on the findings, ATL general secretary Dr Mary Bousted said: "Teachers already have powers to search pupils. Extending and continuing to emphasise these powers will undermine teachers'role as educators, putting them increasingly into a policing role.
"Members are worried that searching pupils risks alienating them and their parents, perhaps even resulting in civil claims and could lead to challenges and confrontation which would have a negative impact on learning."
Schools minister Nick Gibb said last year the government plans to simplify legislation to help teachers get back in control of the classroom.