Behaviour and physical violence is getting worse in primary schools, a survey suggests.
Some 48% of primary teachers reported pupils being physically aggressive, the Association of Teachers and Lecturers poll of more than 1,000 teachers says.
This compared to a fifth of secondary school teachers.
General Secretary Dr Mary Bousted said behaviour was worsening in primaries, but the government said it had made clear its expectations on behaviour.
The Department for Children, Schools and Families said that according to Ofsted, pupil behaviour is good or outstanding in 95% of primary schools.
The findings of the ATL survey of teachers, lecturers, support staff and school leaders in schools and colleges across the UK are being presented at the association's annual conference in Manchester.
It found nearly 90% of staff had dealt with low level disruption such as talking and not paying attention (89%), but over 50% had reported verbal attacks, and nearly 40% intimidation.
Some 83% of staff had reported physical aggression such as pushing and shoving, while 48% had reported the use of fists and 42% the use of legs.
Sixty four staff had reported having been physically harmed by a student.
Over a quarter of school and college staff have had to deal with physical violence from a student, and just over a third had been confronted by an aggressive parent or guardian, the survey said.
ATL general secretary Mary Bousted told Today: "We think at primary schools behaviour is definitely getting worse."
Nearly half of those questioned believed that behaviour in the classroom had become worse over the past two years, while 60% thought it had worsened over the past five.
Child benefit penalty
She said her members were proposing parents whose children repeatedly misbehaved should be given parenting classes, which she assumed would be compulsory.
If this did not work, they should lose some of their child benefit, members will say.
Carrie Longton, one of the founders of the Mumsnet website, said: "They [parents] feel really strongly that removing benefit doesn't have any realistic chance of making things any better.
"We think, as parents, class sizes are a problem," she added.
But Dr Bousted said research in other countries had shown this was not the most important indicator in explaining bad behaviour.
She said she had found, from her time as a teacher, that she had never got to meet the parents she had wanted to meet the most.
"They were simply absent from their children's lives," she said.
"We must say that there are certain standards we need you to adhere to to bring up your children."
Staff in state schools reported higher levels of disrespect, verbal abuse, physical attacks and intimidation than those in private schools.
Schools Minister Vernon Coaker said: "Good behaviour and an atmosphere of respect should be the norm in all schools.
"We have given head teachers clear legal powers to enforce discipline which means they can get tough on poor behaviour without fear of being taken to court, including using reasonable force to control or restrain pupils.
"We want behaviour to be good in every school and later this week Ed Balls will announce the next steps on improving behaviour."
Tory leader David Cameron said the rules needed to be changed to enable teachers to instil discipline, order and good values in schools.
He said teachers needed to be freed from the constraints hampering their ability to stop pupils misbehaving.
"Home-school contracts" should be signed by both children and parents to improve classroom behaviour, he added.