Suspensions across the Riverina region - covering an area roughly from Cootamundra to the South Australian border - rose from 619 in 2010 to 765 in 2012, an increase of more than 23 per cent in just two years.

A spokesman for the Department of Education and Communities said the sharp rise in suspensions and expulsions was not necessarily related to a rise in bad behaviour.

"In the Riverina in the last five years, there has been little fluctuation in expulsions for 'behaviour'," the spokesman said.

"The only significant change was an increase for 'participation' compared to previous years in 2012, coinciding with the transition to the new school leaving age."

But the department's own figures on expulsions - which it differentiates only between 'misbehaviour' and 'unsatisfactory participation' in its publicly available figures - tell another story.

Just one student in the Riverina was expelled for misbehaviour in 2010.

The next year, that number rose to eight and in 2012, the last year the department has reported on expulsions to date, there were nine students told to find another school.

Riverina schools did, however, record the second-lowest rate of serious incidents in term 4 last year according to the department's figures.

Of the 19 incidents in the region noted by the department, six were assaults while seven fell into the "other" category.

In what appears to be the most serious incident during that period, a student was hospitalised after being punched repeatedly in the face, jaw and side of the head by a classmate during a school sport activity.