The state's curriculum watchdog has also penalised a student who continued to write after an exam ended.

But the number of students cheating in the high-stakes exams continues to decline.

The Victorian Curriculum and Assessment Authority punished five students for "serious breaches" of VCE exam rules in 2014, including two students who copied their classmates' multiple-choice answers.

These students had their marks reduced by one to three grades.

It investigated 38 alleged breaches of exam rules in 2014, down from 54 the previous year.

While some students had their marks reduced, others received reprimands and were cautioned for minor breaches where there was "no intention to cheat".

The authority decided to take no futher action against 18 minor incidents it investigated.

VCAA board chairman Chris Wardlaw said cheating was a waste of time, and unfair.

"For the sake of the overwhelming majority of honest VCE exam candidates, we must penalise those very few who seek an unfair advantage,"

He was pleased there had been a decline in investigations involving students flouting the rules with mobile phones, he said.

There were nine investigations involving mobile phones last year, down from 16 the year before.

One student who used their phone to search the internet for exam answers had their grades reduced.

Schools were doing a good job ensuring students understood exam rules, Mr Wardlaw said.

"Our trained examination supervisors also continue to be vigilant."

henrietta.cook@fairfaxmedia.com.au