Children as young as five are displaying worrying sexual behaviour at school, prompting concerns that teachers are ill-equipped to differentiate between whether students are victims of sexual abuse or are imitating what they see in music videos or internet advertising, new research reveals.

Lesley-anne Ey, a lecturer in child development, educational psychology and child protection at the University of South Australia, said research shows teachers feel they don't know enough about problematic sexual behaviours to confidently manage increasing incidences in Australian schools.

In newly published research in the journal Sex Education, Dr Ey asked more than 100 teachers from government, independent and Catholic primary schools across Australia about their experiences with children's problematic sexual behaviours, and their management strategies in schools.

She said she was surprised to discover that 40 per cent of teachers involved in the research reported witnessing problematic sexual behaviour in schools, including simulated intercourse, attempts to coerce other students into sexual conduct, and in one case, a year 4 child who threatened to rape other students.