Statistics released yesterday showed 19 Otago pupils breached the rules in 2017 - up from the six who breached the rules in 2016.
In Southland, the figure has remained static at four pupils.
NZQA assessment division deputy chief executive Kristine Kilkelly said 379 pupils were investigated nationwide, and 353 were found to have breached the rules.
Breaches included 117 pupils having a cell phone in the exam room, six pupils were caught using a cell phone in an exam, 93 had notes in the exam room, 28 had unauthorised material, 46 were caught communicating with another candidate, and 11 were found to have used inappropriate or offensive material/language.
When NZQA received a report of a possible breach, a letter was sent to the pupil involved, along with copies of any relevant information or reports about the possible breach, she said.
Those involved were invited to make a written comment to NZQA.
"An investigation may include consultation with the school or other agencies, and/or a face-to-face meeting with the student(s) concerned.''
NZQA used independent contractors to advise on progress and recommend decisions, she said.
While Otago numbers were relatively low, Otago Secondary Principals' Association secretary Gavin Kidd was concerned by the sudden surge in the latest statistics.
"I'm sure the affected schools, both locally and nationally, would be concerned. I know I would be if it was my school.
"It's good that students not following the rules are being identified.
"Schools will be concerned, and principals, principal nominees and centre managers will be working hard to educate students so that that trend doesn't continue.''
Nationwide, there had been an increase of 4.4% in breaches between 2016 and 2017.
The statistics show Canterbury also experienced a major surge, going from 21 in 2016, to 35 in 2017 (a 66.6% increase), and Wellington went from 33 to 41 (a 33.3% increase).
Auckland went from 167 to 174 (a 4.2% increase) after having significantly lower numbers in the past five years.
