Primary school students are increasingly being farmed out to other classes when their teacher is away in a cost-saving move that teachers say is harming children's learning.

The practice - known as grade-splitting - involves dividing students into small groups and distributing them in other year levels when a teacher is sick or absent instead of hiring a casual-relief teacher.

Teachers claim grade-splitting is disruptive to learning because it blows out class sizes and can mean, for example, that a group of year 5s are sent to a prep class, often without 

An AEU survey of 590 primary teachers found grade-splitting occurred at 87 per cent of respondents' schools to cover staff illness, planning time, excursions, camps, swimming and professional development.

More than 40 per cent said it occurred all year round and 56 per cent said there were space concerns when it occurred.

Australian Education Union officer Marino D'Ortenzio said a meeting of the Casual Relief Teacher Association last week had identified grade-splitting as an issue of significant concern.

"Schools are in the invidious situation where they have to choose between casual-relief teachers and programs," he said.

Opposition education spokesman James Merlino said Labor opposed grade-splitting.

"The cuts of the Napthine government over the last four years have meant schools have had to be creative in reducing costs ... this is certainly one way to do it," he said. "Unfortunately, it is not in the best interests of our kids' learning outcomes, and Labor does not support this practice."

In response the government says "I know our school leaders are making decisions to benefit their students, and I encourage the AEU to do the same."

Casual-relief teacher Stephanie Schiller said grade-splitting was common, particularly in larger schools.

She said students often misbehaved because the "busy work" they were given in their teachers' absence - mostly worksheets and writing activities - did not keep them engaged.

"Behaviour is a big concern but, even more so from an educational standpoint, putting kids on the floor to do busy work I think is terrible policy."

Grade splitting is not unusual and has been happening forever. ( I remember as a schoolboy myself going to other classes for short periods of time during our school swimming program when classes were split up according to swimming ability and it is not uncommon to move children again for short periods of time as a form of 'time-out' for the child and often the child's class) However I have heard more and more of instances where schools have not budgeted sufficiently to cover staff absences either due to illness or professional learning and instead of employing CRTs they divide up classes and send children off with 'busy work' for the day. This is not genuine cross-age tutoring but baby sitting. It does not happen at Glen Park and parents in other schools where this is common practice have a right to be angry if their child is spending too much time sitting on the floor in someone else's classroom doing busy work.

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